Arizona State Retirement System, Phoenix, will raise its employer and employee pension contribution rate for its $18.8 billion 401(a) plan to 5.2% from 2% for the 2004 fiscal year, beginning July 1, said David Cannella, spokesman. The state Legislature approved the increase to cover market losses and new benefit enhancements, he said. The plan is 105% funded, down from a high of 118% in 1999. The previous contribution rate was artificially low, Mr. Cannella said, with the difference made up by investment gains. The new rate has been set for a minimum of two years.