MetaPostCount Insight - How often do you talk about the network on the network


References #1977
"@reflection used Twitter to talk about Twitter 1 time this week. That's roughly 100% of @reflection's tweets for the week." 

Two comments:
* "1 time" or "2 times" reads a bit awkward to me here. Can we use InsightTerms::getOccurrencesAdverb to get "once" or "twice"?
* Can we drop "roughly"?

@adampash @anildash