Sales of new U.S. homes fell in March by the biggest amount in more than a year, the government reported Tuesday. The Commerce Department said sales fell 7.1 percent in March to an annual rate of 328,000 units. While March sales slowed, sales had made significant gains in February and January. The March weakness could reflect that a warmer-than-normal winter caused sales that normally happen at the beginning of the spring season in March to occur in February instead. Compared to a year earlier, March new-home sales were up 7.5 percent. Despite the year-over-year improvement, sales of new homes are only about half the 700,000-unit annual pace that analysts consider evidence of a healthy housing market. The weak housing market has been showing signs of recovery so far this year, helped by low prices, record-low mortgage rates, and some improvement in hiring that has lowered the unemployment rate. It is now cheaper to buy a home than rent in much of the country.