<ol>
{% for month in site.home_section.months  %}
    {{ site.home_section | monthly_articles: month | size | assign_to: 'articles_count' }}
    {% if articles_count > 0 %}
        <li>{{ site.home_section | link_to_month: month }} ({{ articles_count }})</li>
    {% endif %}
{% endfor %}
</ol>