Toyota Motor Co. is expected to announce an expansion of its light-truck plant being built near Tijuana, Mexico, according to industry analysts. Toyota last year said the plant would cost $140 million and would produce 20,000 Tacoma pickups and 170,000 truck beds a year."There are bigger plans for Baja than 20,000 Tacomas," said Alan Baum, director of forecasting for the auto-industry consulting firm Planning Edge in Farmington Hills. "Every time they've put a facility in it's been a starting point for something that's become much more significant." Toyota has said it wants to raise its global market share to 15 percent by the end of the decade from about 10 percent. This year, the company has announced capacity increases in North America including a new pickup plant in San Antonio, Texas, and expansions of engine and parts plants in Alabama, California and Canada. Analysts estimate Toyota earns more than 80 percent of operating profit in the region.