U.S. service industries expanded in September at a slower pace than forecast, indicating a pause in the momentum of the biggest part of the economy before the federal government went on hiatus, according the Institute for Supply Management, Bloomberg reported. The institute reported earlier this month that manufacturers were operating at their highest pace since April 2011. Its non-manufacturing index dropped to 54.4 from the prior month's 58.6, the biggest decrease since November 2008. A reading above 50 shows expansion. The median estimate in a Bloomberg survey of economists was 57.