And lots if them.
"On average, they switched between devices including mobile phones, tablets and laptops 21 times over the hour. Despite this, 95 per cent of people had the television on for the entire hour."
http://www.brandrepublic.com/news/1225960/people-swap-devices-21-times-hour-says-omd/
Anecdotal evidence here tends to confirm this --particularly in the 20-something demographic. Slower for the over-60 group, but not by much.
When there's advertising everywhere no one can see it I guess.