Attribute caps

i have seen in prior post that the cap is 15 on a single attribute, has anyone tested this? im currently 15 in Air using a storm eye and a major rune and was thinking of using a superior rune to try and get to 16 but if i cant get there i dont want to waste the cashola to try... can i get a 100% confirmation that 15 is the limit on a single attribute?

16 is it

3+ superior rune
1+ headpiece

great.. i thought it was 15.. thanks for the help

It is 16... I have done that with my ranger and expertise