You'd be surprised. This is in Canada, not sure about the US.
Deaths per 100,000 people (drowning), Canada, 2006-2010:
0-4: 1.1
5-12: 0.6
13-17: 0.9
18-24: 2.2
24-34: 1.6
34-49: 1.4
50-64: 1.7
65+: 1.6
I don't have the source handy, but I'll try to dig it up.
Edit: Source - http://www.lifesavingsociety.com/media/157475/2013-cdndrowni...