Short version: A LOT. Like… a lot a lot.
For instance, a dormant, stationary Android phone (with the Chrome browser active in the background) communicated location information to Google 340 times during a 24-hour period, or at an average of 14 data communications per hour. In fact, location information constituted 35 percent of all the data samples sent to Google.
And that's just scratching the surface! You can read the full report here: https://digitalcontentnext.org/wp-content/uploads/2018/08/DCN-Google-Data-Collection-Paper.pdf
I would love to see a followup with how much info Apple collects with OSX/iOS as well as one on Facebook and Amazon's data collection.