this is a bit out of date ( it's probably worse now ) but through 2003....
These are total light vehicle sales (in millions of units) of domestic
and import car and trucks broken down by automatic and manual
transmissions:
Year Automatic % Manual % Total
1985 10,021,482 , 77.6% , 2,887,171, 22.4%, 12,908,653
1990 10,141,794, 78.7%, 2,752,150, 21.3%, 12,893,944
1995 12,816,559, 83.1%, 2,602,211, 16.9%, 15,418,770
2000 15,995,874, 90.0%, 1,785,377, 10.0%, 17,781,251
2001 14,898,961, 90.6%, 1,540,618, 9.4%, 16,439,579
2003 16,752,979, 92.6%, 1,335,531, 7.3%, 18,088,510
*Includes manual/automatic hybrids
Source: Ward's Communications