I have a site with adsense since 2006, site is non-english with more then 3.000.000 pageviews/month, however i put a small area in english.

In the end of December revenue drop almost 30%, what's up, i don't know, site have more a less same number of visitors and pageviews.

In the end of JAN i put new english content language when i saw some visitors from US and put new original content.

Pageviews increase in english area, but ... in amost daily basis, many clicks was removed(i never had this issue), all from US and all with hight value. Today for example, i had in starting hours 194 clicks, 13 was removed (almost half of total revenue). Seems a High value filter (i don't believe but in last days... )

I check server logs, not analytics, and, from US i only see spiders (good ones), anyone know what is this ?