<ol>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
  <li>333,333.33</li>
  <li>111,111.11</li>
  <li>222,222.22</li>
</ol>

ol {
  column-width: 9em;
  counter-reset: num;
  list-style-type: none; 
}

li {
  font-size: 0.9em;
  line-height: 2em;
}

li:nth-child(2n) {
  background-color: #eee;
}

li:before {
  content: counter(num);
  counter-increment: num;
  display: inline-block;
  width: 2em;
  padding-right: 1em;
  text-align: right;
}