Sorry, I'm a little late responding here... However, using valid markup is important and therefore I think it's worth mentioning alternative solutions...
Option 1
Using a little HTML and CSS, you could set the value on each li ([ Valid HTML5 ]):
[ JS Fiddle Example ]
HTML
<ol>
<li class="col-xs-6" value="1">Row 1, col 1</li>
<li class="col-xs-6">Row 1, col 2</li>
<li class="col-xs-6" value="2">Row 2, col 1</li>
<li class="col-xs-6">Row 2, col 2</li>
</ol>
CSS
ol li:nth-child(2n+0) {
list-style: none;
}
Option 2
However, if you're going for a purely CSS approach, this is probably the best option...
[ JSFiddle Example ]
HTML
<ol>
<li class="col-xs-6">Row 1, col 1</li>
<li class="col-xs-6">Row 1, col 2</li>
<li class="col-xs-6">Row 2, col 1</li>
<li class="col-xs-6">Row 2, col 2</li>
</ol>
CSS
ol {
counter-reset: index;
}
ol li:nth-child(2n+0) {
counter-increment: index;
list-style: none;
}
ol li:nth-child(2n+0):before {
content: counter(index) ".";
}
ol li:nth-child(2n+0):before {
content: "";
}
However, do keep in mind [ browser compatibility ].
liinside auland I didn't see any problems in my code, but with theolthe numbers sure do get all messed up.