Pitching speed chart by age

Question
Larry I read a question that you answered about 12U pitching speed. Is the speed taken at the plate or when it leaves the hand. I have a radar gun that gives 2 speeds. One from the hand and one at the plate. So when you talk of girls speed which one is it.
Thanks

Answer
Hello Brad

I think it's an average of the two.

There are variables depending on the maker of the radar gun. The ball does lose some speed after leaving the pitchers hand and by the time it goes over the plate. (My guess is 3 to 6 mph)

I based the speeds on studies and charts done by others.  

These charts are probably based on using the popular Jugs Speed Gun which usually picks ups the speed of the ball after it has traveled 4 to 8 feet.

An example of such a chart can be found here (scroll down to "The Need for Speed"):
http://www.girls-softball.com/2006_02_26_archive.html