The National Association of Home Builders (NAHB) is anticipating an improved demand for new single-family housing this spring.  Their Housing Market Index (HMI) in March showed an increase to 17, one point better than it’s been the last four months, and the highest since May 2010.  The NAHB/WellsFargo HMI monthly survey has been ongoing for 20 years.  It measures builders’ perceptions, based on inquiries from likely prospects and current projects, to gauge where they think the market will go in six months.  Regionally, the results differed.  The Northeast dropped a point to 20, the Midwest remained unchanged at 12, the South gained two points to 20 and the West was up four points to 17.