Interesting, on AZERTY (french) keyboards, parentheses are unshifted. They are on 5 and on ° (the key just right of 0). On the other hand, { is on alt gr on 4, [ on alt gr on 5, ] on alt gr ° and } on alt gr + (right of °). I wonder if it influences the programming languages that people prefer, even just a bit. Or maybe the style? Unshifted parenthesis makes function call easier for example.