LOS ANGELES (AP) — Solid stock market gains and workers putting more of their pay toward their golden years are paying off for many retirement savers. The average 401(k) plan balance grew 24% to a record $129,300 in the second quarter from a year earlier, according to a review of 19.8 million accounts by Fidelity Investments. On average, employees contributed a record 9.3% of their pay to their 401(k) in the second quarter, while some 38% of workers increased their contributions over the last year. Fidelity also found that fewer savers are borrowing against their retirement accounts.