WASHINGTON (AP) — The U.S. economy is on a tear. So why is the American job market limping behind? The Labor Department is expected to report Wednesday that companies, government agencies and nonprofits added 75,000 jobs last month, according to a survey of forecasters by the data firm FactSet. That would be an improvement over December’s 50,000 – but it’s inconsistent with strong economic growth and well short of the hiring boom of just a couple of years ago. Moreover, the January numbers are