Colin Gleadell reports these numbers from Sotheby’s and Christie’s for 2008:

Auction sales at Sotheby’s during 2008 declined slightly from $5.3 billion (£3.6 billion) in 2007 to $4.9 billion. Estimates for Christie’s sales suggest a drop of about 20 per cent from $6.3 billion to just over $4 billion.

Considering the lopsided nature of 2008 with exceptionally strong sales in the first half and weak sales in the second half, it would be meaningless to extrapolate from these numbers.

Art Market News (Telegraph)