Why homes fell out of escrow in 2010

While perusing the Web site of the California Association of Realtors this morning, I came across the 2010-2011 economic forecast done by their chief economist and decided to take another quick look at it. One graph caught my eye: "Reasons why property fell out of escrow".

Here's the tally:

Property fell out of escrow because	2008	2009	2010
Buyer changed mind & decided not to buy	33%	37%	44%
Buyers couldn’t secure a mortgage	33%	41%	30%
Buyer couldn’t come up with down payment	11%	6%	5%
Seller decided not to sell	1%	0%	1%
Other	22%	22%	20%
Total	67%	68%	56%

Am surprised at the fact that nearing half of the escrows that fell apart did so because buyers changed their mind. Anyone have any thoughts on the reason for the buyers' change of heart? Nervousness about the economy maybe?