Data appearing as a "0" does not actually represent "0" units sold. Do to rounding issues "0" refers to less than 500 units sold.
Source: US. Bureau of the Census
US. Bureau of the Census, New Houses Sold by Sales Price Between $300,000 and $499,999 in South Census Region [NHSSPS30T49], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/NHSSPS30T49/, October 8, 2015.