Quarter-Year: Android%/Apple% = ratio

Q2-2010: 33/22 = 1.5

Q3-2010: 44/23 = 1.91

Q4-2010: 53/19 = 2.8

You can find graphs from various sources that show a consistent trend for Android (i.e. the sales in the last month of Q4 are higher than the average and much higher than the sales in the first month) if that wasn't already obvious from the quarterly numbers.

My prediction for sales right now i.e. the month of March is about 60/15 but I guess we'll hear the Q1 numbers in a month or so and it'll be something like 3.5 overall.

edit: a final note, this isn't a prediction that Apple sales will fall, they'll certainly grow (though I think their U.S. marketshare just peaked) it's simply that Android's massive growth will expand the smartphone market and shrink their sales share.