GM sales fell 6% for year through Nov
2008 sales expected to be flat or worse compared w/ this year
Up to 56K of GM's 74.5K blue-collar workers could retire by 2011
Many replacements will fall into the lower-wage tier
New worker in lower-tier job will cost GM $25.65 in wages and benefits
Under one-third of the $78.31 it presently spends