The head of the Public Employee Retirement System told lawmakers Thursday that the retirement contribution rate has to increase by 2 percent for the coming biennium.Since that premium cost is split 50-50 between the employee and the state, it translates to a 1 percent cut in take-home pay for all state workers. For many school district and local government employees, those premiums are paid 100 percent by the government involved so only the employers, not the workers, are impacted.The reason for the increase boils down to the fact that the cost of supporting the program must be borne by a …