WASHINGTON — U.S. home prices rose in September from a year earlier at the fastest pace in 13 months as a lack of houses for sale has forced buyers to bid up available properties.

The Standard & Poor’s/Case-Shiller 20-city home price index, released Tuesday, increased 5.5 percent in September compared with a year ago, the largest annual gain since August 2014. Steady job gains and low mortgage rates have propelled a solid rebound in home sales, which are on track to reach the highest level since 2007. The unemployment rate fell to 5 percent in October as employers added the most jobs since December. Borrowing costs have ticked up but remain below 4 percent, a low level historically.

Sales of existing homes, while improving, have been volatile this year. They slipped in October after a healthy jump the previous month, according to the National Association of Realtors.

Overall, home sales have increased 3.9 percent in the past 12 months. At the same time, the number of available homes has fallen 4.5 percent.

That squeeze has pushed up prices. The typical home sold for $219,600 last month, up nearly 6 percent from a year ago, the Realtors group said Monday. That is the highest median price for the month of October since October 2005, at the height of the housing bubble.

Home prices are rising at more than double the pace of inflation and much faster than wages, pricing many Americans out of the housing market. That has also pushed up rents as Americans increasingly stay in apartments.