home sales fell as they normally do from December but rose nearly 10 percent above a year ago to the highest level for that month in four years. The portion of homes sold to investors and others paying cash was at record levels, creating especially robust sales in the sub-$100,000 market. That helped push the median sale price down to a nearly 15-year low of $118,000, a real estate information service reported. A total of 3,669 new and resale houses and condos closed escrow in the Las Vegas-Paradise metro area (Clark County) last month ? the highest for a January since 2007. Last month?s sales tally was down 20.8 percent from December but up 9.9 percent from a year earlier, according to DataQuick Information Systems of San Diego. The firm tracks real estate trends nationally via public property records.