In my experience very few Americans set their A/C to anything above 75F.
It's hard to accurately generalize an entire country, of course. But in my experience people generally are in the range I stated. I'm sure that there exist people who turn their AC down below 70F, but I've never personally encountered one. And even the low end of my range, 72F, is uncommon in my experience.
In my experience they absolutely do. The houses by and large aren't very well designed or insulated, and electricity isn't that cheap. In the southeast I rarely see home thermostats set to the 60s or low 70s. Office settings are a different question, though.