I have wondered this for a long time…
 
How much caffeine is in decaf?
 
Now I know.  AND I can give side-by-side comparison of various caffeinated liquids.
 

Qty (ml)
Caffeine (mg)
Caffeine/8oz
Caffeine / standard container
Coffee
350
222
171.6
171.6
Red Bull
250
80
61.8
123.7
Chocolate Milk
500
14
10.8
10.8
Cola
406
41
31.7
47.5
Tea
240
24
18.5
18.5
Decaf Coffee
350
4
3.1
3.1
 
The above table tells me that a cup (8oz) of decaf has 1% of the caffeine of it’s full-bodied brother.
 
Additionally, since my source data purported to compare caffeine/ml it did not use a standard so I could not see the relative ranking of each.
 
For all the hype of Red Bull it’s only 1/3 the caffeine of a standard cup of coffee, and a cola is 1/2 of that.
 
Even a 16 ounce can of Red Bull does not match the caffeine in one cup of coffee at my diner down the street.
 
So tell me, why are we so concerned about our kids and their consumption.  Many coffee drinkers I know consume more than 1,700mg of caffeine daily.