By The Associated PressThe U.S. economy added 146,000 jobs in November, slightly better than October's gain. At the same time, the unemployment rate fell to 7.7 percent from 7.9 percent. Hiring at about 150,000 a month usually doesn't push down the unemployment rate so much. Why did the rate fall that far? Because the government does one survey to learn how many jobs were created and another survey to determine the unemployment rate. Those surveys can sometimes produce different results. One is called the payroll survey. It asks mostly large companies and government agencies how many people they employed during the month. This survey produces the number of jobs gained or lost. In November, the payroll survey showed that companies added 147,000 jobs, and federal, state and local governments shed 1,000. The other is the household survey. Government workers ask whether the adults in a household have a job. Those who don't are asked whether they're looking for one. If they are, they're considered unemployed. If they aren't, they're not considered part of the work force and aren't counted as unemployed. The household survey produces each month's unemployment rate. In November, the household survey showed that the number of people who said they were either working or looking for work declined by 350,000. Of that group, 229,000 were unemployed but stopped looking for work in November. Another 122,000 who were employed in October left their jobs last month to retire or for other reasons. Those factors pushed down the unemployment rate. Unlike the payroll survey, the household survey captures farm workers, the self-employed and people who work for new companies. It also does a better job of capturing hiring by small businesses. But the household survey is more volatile from month to month. The Labor Department surveys just 60,000 households, a small fraction of the more than 100 million U.S. households.