* Sempra Energy, San Diego-based parent of the nation’s largest natural gas distribution utility, plans to increase deregulated retail sales of gas and electricity to account for a third of the company’s earnings by 2003. In 1999, the company’s two big utility subsidiaries, Southern California Gas Co., based in Rosemead, and San Diego Gas & Electric Co., accounted for 95% of total profit. By 2003, Sempra is aiming for earnings in its non-utility units, including international, trading, technology, financial, retail industrial and household sales, to account for a full third of profit, spokesman Doug Kline said. The company plans to raise revenue generated from its commercial and industrial retail sales of deregulated energy to $2 billion by 2003 from $200 million last year. Sempra shares fell 19 cents to close at $17.31 on the NYSE.