FACTBOX: Key facts about March auto sales

DETROIT (Reuters) - March auto sales fell 12 percent from a year earlier on an unadjusted basis, according to data from auto manufacturers on Tuesday. The following are highlights from the largest carmakers in the U.S. market.

Overall industry

* Total light vehicle sales -- 1.36 million units.

* First quarter sales -- 3.6 million units, down 8 percent.

General Motors Corp GM.N

* Light vehicle sales down adjusted 12.7 percent (277,751 units), unadjusted sales down 19 percent

* Year-to-date sales down 9.7 percent

* Inventories at month-end: 874,000 units

* Cars/trucks: Car sales down adjusted 8 percent/light truck sales down 15.7 percent

* Retail/fleet mix: retail 77 pct, 23 percent fleet

* Market share: 20.7 percent including Saab

* Key vehicles: Chevrolet Impala up 9.6 percent, Chevrolet Malibu up 7.3 percent, Chevrolet Silverado down 17.6 percent, Chevrolet Tahoe down 29.1 percent, GMC Sierra up 3.9 percent.

* Incentives: average $3,271 per vehicle, up from $2,832 a year earlier.

Toyota Motor Corp (7203.T)(TM.N)

* Vehicle sales down adjusted 3.4 percent (217,730 units), unadjusted sales down 10 percent

* Year-to-date sales down 4.4 percent