Returns average number of tags per question on a site.
Additionally it also returns tag count breakdown with question counts.
Best viewed as "Text-only results"
Q&A about the site for academics and those enrolled in higher education
with Counts as (
len(Tags) - len(replace(Tags, '<', '')) as Tags,
count(*) as QuestionCount
where PostTypeId = 1
group by len(Tags) - len(replace(Tags, '<', ''))
select cast(sum(Tags * QuestionCount) as decimal) / sum(QuestionCount)