Apparently the younger you are, the more you can hear. Go down the list of high frequency pitches on this site and basically you just select which was the last one you can hear then it tells you your results. I got 14.9 kHz and this is what I got:
You are a thirtysomething
You're a little frustrated that you can't hear all the tones that the young 'uns can but will be more than happy if it means you don't have to listen to their damn ringtones on the bus anymore.
The highest pitched ultrasonic mosquito ringtone that I can hear is 14.9kHz
o_O It's about 10 years off, but that would be caused by all my years of listening to loud music are paying off

LOL.
http://www.ultrasonic-ringtones.com/