Google has measured 1 billion+ store visits from AdWords ads globally

To help close the online-to-offline attribution gap, Google introduced store visits tracking and measurement in AdWords in December, 2014. Since that time, the company says, it has measured more than 1 billion store visits globally in its effort to show the impact of online advertising on in-store traffic.
In addition, AdWords store visits measurement is now available to 1,000 advertisers in 11 countries, including automotive dealers, Google announced at its annual Performance Summit on Tuesday.

http://searchengineland.com/google-1-billion-store-visits-measured-250237
http://searchengineland.com/hood-google-adwords-measures-store-visits-222905