Mac User Disappearing

Hi there, i have an odd question: I experience an massive drop of mac user traffic to my sites over the last 18 mounth, especially the last 3/4 mounth. Up to 85% been lost since mid 2011 with an avrage of 13/15.000 a day to about 1500 !!! Mac user must be disappearing in there 1000s a week/day for what reason ??? iOS hype? All my development and sites are in good practice, clean coded, and world wide reconiced( included sevel number 1s on apple.com Dashboard download site...) - I generated more then 10mil of downloads over the years and now it is completly dead - What happen?