Probleme de trier avec Jquery sur des %

Bonjour,

je suis entrain de faire un tableau triable avec Jquery pour cela j'utilise un script sorttable.js que j'ai trouvé sur internet.
mon probleme est que dans ce tableau j'ai des pourcentages mais le trie ne se fait pas correctement: 1%-10%-100%-11%-19%-2%-20%. je n'arrive pas a voir ou changer le code que voici pour que l'ordre soit correct:

addEvent(window, "load", sortables_init); 

var SORT_COLUMN_INDEX; 

function sortables_init() { 
    // Find all tables with class sortable and make them sortable 
    if (!document.getElementsByTagName) return; 
    tbls = document.getElementsByTagName("table"); 
    for (ti=0;ti<tbls.length;ti++) { 
        thisTbl = tbls[ti]; 
        if (((' '+thisTbl.className+' ').indexOf("sortable") != -1) && (thisTbl.id)) { 

            //initTable(thisTbl.id); 
            ts_makeSortable(thisTbl); 
        } 
    } 
} 

function ts_makeSortable(table) { 
    if (table.rows && table.rows.length > 0) { 
        var firstRow = table.rows[0]; 
    } 
    if (!firstRow) return; 

    // We have a first row: assume it's the header, and make its contents clickable links 
    for (var i=0;i<firstRow.cells.length;i++) { 
        var cell = firstRow.cells[i]; 
        var txt = ts_getInnerText(cell); 
        cell.innerHTML = '<a href="#" class="sortheader" onclick="ts_resortTable(this);return false;">'+txt+'<span class="sortarrow">   </span></a>'; 
    } 
} 

function ts_getInnerText(el) { 
 if (typeof el == "string") return el; 
 if (typeof el == "undefined") {  
            return el 
        }; 
 if (el.innerText) return el.innerText; //Not needed but it is faster 
 var str = ""; 

 var cs = el.childNodes; 
 var l = cs.length; 
 for (var i = 0; i < l; i++) { 
  switch (cs[i].nodeType) { 
   case 1: //ELEMENT_NODE 
    str += ts_getInnerText(cs[i]); 
    break; 
   case 3: //TEXT_NODE 
    str += cs[i].nodeValue; 
    break; 
  } 
 } 
 return str; 
} 

function ts_resortTable(lnk) { 
    // get the span 
    var span; 
    for (var ci=0;ci<lnk.childNodes.length;ci++) { 
        if (lnk.childNodes[ci].tagName && lnk.childNodes[ci].tagName.toLowerCase() == 'span') span = lnk.childNodes[ci]; 
    } 
    var spantext = ts_getInnerText(span); 
    var td = lnk.parentNode; 
    var column = td.cellIndex; 
    var table = getParent(td,'TABLE'); 

 var startline=1; 
 if (document.getElementById(table.id+'_tbody')) { 
  startline = 0; 
  table = document.getElementById(table.id+'_tbody'); 
 } 



    // Work out a type for the column 
    if (table.rows.length <= 1) return; 
    var itm = ts_getInnerText(table.rows[1].cells[column]); 
    sortfn = ts_sort_caseinsensitive; 
   if (itm.match(/^\d\d[\/-]\d\d[\/-]\d\d\d\d$/)) sortfn = ts_sort_date; 
    if (itm.match(/^\d\d[\/-]\d\d[\/-]\d\d$/)) sortfn = ts_sort_date; 
    if (itm.match(/^[£$]/)) sortfn = ts_sort_currency; 
    if (itm.match(/^[\d\.]+$/)) sortfn = ts_sort_numeric; 
    SORT_COLUMN_INDEX = column; 
    var firstRow = new Array(); 
    var newRows = new Array(); 
        for (i=0;i<table.rows[0].length;i++) 
        { 
            firstRow[i] = table.rows[0][i]; 
        } 
        for (j=startline;j<table.rows.length;j++) 
        { 
            newRows[j-startline] = table.rows[j]; 
        } 

    newRows.sort(sortfn); 

    if (span.getAttribute("sortdir") == 'down') { 
        ARROW = '  ?'; 
        newRows.reverse(); 
        span.setAttribute('sortdir','up'); 
    } else { 
        ARROW = '  ?'; 
        span.setAttribute('sortdir','down'); 
    } 

    // We appendChild rows that already exist to the tbody, so it moves them rather than creating new ones 
    // don't do sortbottom rows 
    for (i=0;i<newRows.length;i++)  
    { 
        if (!newRows[i].className || (newRows[i].className && (newRows[i].className.indexOf('sortbottom') == -1))) 
            table.tBodies[0].appendChild(newRows[i]); 
    } 
    // do sortbottom rows only 
    for (i=0;i<newRows.length;i++)  
    { 
        if (newRows[i].className && (newRows[i].className.indexOf('sortbottom') != -1)) 
            table.tBodies[0].appendChild(newRows[i]); 
    } 

    // Delete any other arrows there may be showing 
    var allspans = document.getElementsByTagName("span"); 
    for (var ci=0;ci<allspans.length;ci++) { 
        if (allspans[ci].className == 'sortarrow') { 
            if (getParent(allspans[ci],"table") == getParent(lnk,"table")) { // in the same table as us? 
                allspans[ci].innerHTML = '   '; 
            } 
        } 
    } 

    span.innerHTML = ARROW; 
} 

function getParent(el, pTagName) { 
 if (el == null) return null; 
 else if ( 
            el.nodeType == 1 && el.tagName.toLowerCase() == pTagName.toLowerCase() 
            ) // Gecko bug, supposed to be uppercase 
  return el; 
 else 
  return getParent(el.parentNode, pTagName); 
} 

//fonction pour la date 
function ts_sort_date(a,b) { 
    // y2k notes: two digit years less than 50 are treated as 20XX, greater than 50 are treated as 19XX 
    aa = ts_getInnerText(a.cells[SORT_COLUMN_INDEX]); 
    bb = ts_getInnerText(b.cells[SORT_COLUMN_INDEX]); 
    if (aa.length == 10) { 
        dt1 = aa.substr(6,4)+aa.substr(3,2)+aa.substr(0,2); 
    } else { 
        yr = aa.substr(6,2); 
        if (parseInt(yr) < 50) { yr = '20'+yr; } else { yr = '19'+yr; } 
        dt1 = yr+aa.substr(3,2)+aa.substr(0,2); 
    } 
    if (bb.length == 10) { 
        dt2 = bb.substr(6,4)+bb.substr(3,2)+bb.substr(0,2); 
    } else { 
        yr = bb.substr(6,2); 
        if (parseInt(yr) < 50) { yr = '20'+yr; } else { yr = '19'+yr; } 
        dt2 = yr+bb.substr(3,2)+bb.substr(0,2); 
    } 
    if (dt1==dt2) return 0; 
    if (dt1<dt2) return -1; 
    return 1; 
} 

//fonction pour la monnaie 
function ts_sort_currency(a,b) { 
    aa = ts_getInnerText(a.cells[SORT_COLUMN_INDEX]).replace(/[^0-9.]/g,''); 
    bb = ts_getInnerText(b.cells[SORT_COLUMN_INDEX]).replace(/[^0-9.]/g,''); 
    return parseFloat(aa) - parseFloat(bb); 
} 

//fonction 
function ts_sort_numeric(a,b) { 

    aa = parseFloat(ts_getInnerText(a.cells[SORT_COLUMN_INDEX])); 
    if (isNaN(aa)) aa = 0; 
    bb = parseFloat(ts_getInnerText(b.cells[SORT_COLUMN_INDEX])); 
    if (isNaN(bb)) bb = 0; 
    return aa-bb; 
} 

function ts_sort_caseinsensitive(a,b) { 
    aa = ts_getInnerText(a.cells[SORT_COLUMN_INDEX]).toLowerCase(); 
    bb = ts_getInnerText(b.cells[SORT_COLUMN_INDEX]).toLowerCase(); 
    if (aa==bb) return 0; 
    if (aa<bb) return -1; 
    return 1; 
} 

function ts_sort_default(a,b) { 

    aa = ts_getInnerText(a.cells[SORT_COLUMN_INDEX]); 
    bb = ts_getInnerText(b.cells[SORT_COLUMN_INDEX]); 
    if (aa==bb) return 0; 
    if (aa<bb) return -1; 
    return 1; 
} 

function addEvent(elm, evType, fn, useCapture) 
// addEvent and removeEvent 
// cross-browser event handling for IE5+,  NS6 and Mozilla 
// By Scott Andrew 
{ 
  if (elm.addEventListener){ 
    elm.addEventListener(evType, fn, useCapture); 
    return true; 
  } else if (elm.attachEvent){ 
    var r = elm.attachEvent("on"+evType, fn); 
    return r; 
  } else { 
    alert("Handler could not be removed"); 
  } 
}