California's $9.2 billion budget deficit could grow, due to a proposed change to the investment forecast of CalPERS, California’s pension fund. The rate has not been changed since 2003. In 2010, CalPERS return on investment was over 20%, but it was 1.1% in 2011. If CalPERS decides to adjust its investment forecast from 7.75% to 7.25%, the cost of CalPERS could jump up by $425 million come July 1…