It's huge. Consider not using Google or signing into their or Microsoft systems.

Dylan Curran downloaded all of the data stored on him by Facebook and Google.
Google's data archive was almost ten times larger than scandal hit Facebook's
It dated back to 2008 and revealed a level of detail that shocked the IT expert
He laid out the extent of the private information held on him in a series of tweets

LINK TO ARTICLE

I don't use Google when I can avoid it, using http://ixquick.eu/  ; in stead.