That was strange, thought it was standard to have such stats, anyway here you get the Old Forum stats:
Screen Resolution Visitors % Total
1600 x 1280 3652 2.56 %
1280 x 1024 15532 10.89 %
1152 x 864 2685 1.88 %
1024 x 768 31011 21.74 %
800 x 600 7577 5.31 %
640 x 480 24 0.02 %
Other Resolution 159 0.11 %