A new gauge from Nationwide Mutual Insurance Co. suggests that the national market is in its best shape since 2001 and there’s no reason to fear a national downturn, much less a bursting bubble, Bloomberg reported. Nationwide’s Leading Index of Healthy Housing Markets rose to 109.8 in the fourth quarter. Values greater than 100 indicate a robust industry. The index uses local data in 373 metropolitan statistical areas that are underlying drivers of the housing market, including measures on employment changes, demographics and the mortgage market. Nationwide has a knack for predicting bubbles. Its index showed signs that the housing market was unraveling in early 2005, long before the Standard & Poor’s/Case Shiller index of home prices peaked at the end of 2006.