Absorption defined for the purposes of this chart is: Number of months to sell all listing inventory at the annual pace of sales activity. (The definition of absorption in my market report series  reflects the quarterly pace – nearly the same)
I started this analysis in August 2009 so I am able to show side-by side year-over-year comparisons. The blue line showing the 10-year quarterly average travels up and down because of the change in scale caused by some of the significant volatility seen at the upper end of the market. The pink line represents the overall average rate of the most recently completed month.
Side by side Manhattan regional comparison:
[click images to expand]
Although everything seems to be absorbed at an historically fast pace, co-ops are generally being absorbed more slowly in nearly every price segment below $5M.