Sioux Center's retail sales topped $147.5 million in fiscal 2015 (July 2014 - June 2015), a 4.65% increase over the same period in 2014, according to the Iowa Dept. of Revenue. Sioux Center's taxable retail sales have doubled in the last 15 years.Sioux Center now accounts for more than 40% of the retail sales in Sioux County.