Mortgage rates inched lower Friday in extremely volatile trading following stronger than expected jobs data and continued turmoil in stocks. The economy added 290,000 jobs in April, about 100,000 more than forecast. Meanwhile, the Unemployment Rate, which is calculated on a separate set of data, increased to 9.9% as the labor force grew by 805,000 workers in April. Average Hourly Earnings, a proxy for wage growth, increased at a modest 1.6% annual rate. In other news, global stock markets continued their slide on concerns over the European debt crisis. The Dow Jones Industrial Average has now given up all gains for 2010. Next week will be relatively quiet in terms of new economic data, with the exception of Friday’s release of April Retail Sales figures and Industrial Production. The Treasury will hold large auctions of 3-, 10-, and 30-year securities beginning Tuesday.