Gasoline isn’t the only fuel experiencing a big increase in price. The state’s largest natural gas supplier says its cost has increased dramatically.MidAmerican Energy Spokesman Kevin Waetke says the price of natural gas has nearly doubled since March. Waetke says it’s a supply problem.as many producers are getting out of the business while industrial customers are switching to natural gas and increasing the demand in what is normally a slow time. Waetke says things could turn around before winter, and heavy residential usage arrives. He says suppliers might want to get back into the business with industrial use increasing.He says the price increase probably won’t hit your gas bill until later in the year as most people don’t use much gas this time of year.MidAmerican provides natural gas to 638-thousand customers in Iowa.