Three out of four above the age of 13...Oldest turns 18 next week. No request for addition allowance tendered, but the week is young;).
Rip: Sounds like you're a pretty lucky man, too.
Oh, and here's my favorite parenting saying...
"When I was 18 years old, I couldn't believe how dumb my dad was. When I turned 21, I couldn't believe how much he'd learned in just three short years!"