Just found the topic by chance but found it quite interesting!,
, and the comments quite valuable.
I was sorry to learn that white and green teas has potentially as much caffeine as other teas.
Anyway, I would like to add a word of caution. When steeping the tea we are extracting water soluble compounds from the leaves, the amount we extract depend on the quantinty of leaves we use, the steeping time and the water temperature. So some of the data on caffeine on the caffeine content of the leaves give us a maximum value of the caffeine we may expect in our cup.