Good news for DTE Energy customers: They can expect a nearly 9% drop in their April gas bills.The utility announced today that it is lowering the gas rate, something made possible by falling natural gas prices and the company's efforts to store natural gas when prices are at their lowest.The savings will impact both residential and business customers, officials said. Residential customers’ overall natural gas bills have dropped by 27%, or about $300 annually, over the past 10 years as the cost for the natural gas DTE buys has declined