In September, sales of newly built single-family homes increased 14 percent from the month before, according to new numbers from the U.S. Census Bureau and the Department of Housing and Urban Development. The improvement exceeded economists' expectations and pushed sales to their highest level since March. But despite the gains, new home sales are still 17.6 percent lower than they were at the same time last year. Why? Well, affordability is a big part of the reason sales trail last year's pace. For example, the median price of a new home has risen 18.7 percent over the past year. And the majority of new homes sold are in the $200,000 to $749,000 price range, with just 2 percent of September sales falling in the under-$200,000 price range. Still, sales increased in just about every region of the country, with the South, West, and Northeast all seeing improvements. The Midwest was the only region that didn't see an increase in September.