count in order according to class - with counter

HTML

<ul>
    <li class="count">one</li>
    <li class="count">two</li>
    <li class="count">three</li>
    <li class="count">four</li>
    <li>blabla</li>
    <li class="count">five</li>
    <li class="count">six</li>
    <li>blabla</li>
    <li class="count">seven</li>
</ul>

CSS

ul {
        list-style-type:decimal;
        padding-left: 30px;
    }
    li {
        display: block;
    }
    li.count {
        display: list-item;
    }