February 2016 and early March were quiet months for spam in Google Analytics.
In mid-March, 2016, rankchecker.online began annoying may websites. In mid-June, it morphed into site-auditor.online.
In late May, monetizationking.net started up, and recently (October) morphed into 24x7-server-support.site.
In the last week of April, first week of May, there was a flurry of fake direct visits to non-existent landing pages, fake organic search keywords, fake Twitter and Facebook referrals.
There have been a couple of hundred other spam sources, mostly of smaller volume and short duration.
Complete information about the spam problem and current filter expressions are available here: