Home prices rose in nearly all major U.S. cities in April from March, further evidence of a housing market that is slowly improving even while the job market slumps. The Standard & Poor’s/Case-Shiller home price index released Tuesday showed increases in 19 of the 20 cities tracked. That’s the second straight month that prices have risen in a majority of U.S. cities. And a measure of national prices rose 1.3% in April from March, the first increase in seven months. San Francisco, Washington and Phoenix posted the biggest increases in April. Prices fell 3.6% in Detroit, the only city to record a drop. The month-to-month prices aren’t adjusted for seasonal factors. Still, prices in half of the cities are up over the past 12 months.