The following {{ plural('bug has', data, pword='bugs have') }} many duplicates:

{% for i, (bugid, summary, creation, last_change, dupe_count) in enumerate(data) -%} {% endfor -%}

Bug	Summary	Creation	Last comment	# of dupes
{{ bugid }}	{{ summary \| e }}	{{ creation }}	{{ last_change }}	{{ dupe_count }}