If I were to write an honest depiction of a day in my life as a teenager, it would be FILLED with swear words!
I had one friend who only used the f-word as an adjective - yeah, no other adjectives existed for him. Another used the s-word about each tenth word. My dad's favorite phrase was G-D, and my oldest sister swore like a marine (not the Gomer Pyle variety, but a real Marine). Me and my other sister didn't swear much - it was just everyone else around us.
Even my mom used the s-word far too often, and most my other friends swore about average for teens. I heard teachers swear, and coaches, of course, did it a lot.
I think my teen years would have been rated 'R' just for the time I spent in school!