That was theory... The actual attack rate increase is not quite as high.
i did some rough tests with haste pots here
for unhasted greataxe i managed to get 102 per minute vs 81 auto attack (26% increase)
The highest increase i got was with a hasted greataxe was 132 vs 101 autoattack (31% increase)
Shade's video below on the same post(a more accurate full minute test) shows about 138 swings per minute hasted (37% increase)