caffeine content by weight of dry coffee?

[psychojoe]

Yo. Google only tells me the estimated caffeine content per volume of drink, which is useless because I may be making it more or less concentrated. Does anyone know roughly the caffeine content per dried weight of instant coffee. A range or very rough idea would be fine

caffeine is awesome, i can totally feel it, now im gonna run, although only like 1.5 miles cuz im too lazy for more atm