WASHINGTON (AP) — U.S. home prices increased at the fastest pace in seven years in January as the pandemic has fueled demand for single-family houses even as the supply for such homes shrinks.

The S&P CoreLogic Case-Shiller 20-city home price index rose 11.1% in January from a year earlier. That’s the biggest gain since March 2014. Prices rose in all 20 cities, and the 12-month increase was larger for all cities in January than in the previous month.

ìJanuaryís data remain consistent with the view that COVID has encouraged potential buyers to move from urban apartments to suburban homes,î said Craig Lazzara, Managing Director and Global Head of Index Investment Strategy at S&P DJI. It’s not yet clear whether that trend will fade as the pandemic is brought under control, Lazzara said, or if there will be a permanent shift higher in demand.

The biggest price gain was in Phoenix, where home prices jumped 15.8%, followed by Seattle, with a 14.3% gain, and San Diego, at 14.2%.

Home sales have jumped in the past year, driven by a desire for more space among those Americans fortunate enough to keep their jobs. With roughly one-quarter of workers doing their jobs from home, along with children going to school online, families have sought out houses rather than apartments, or moved to larger homes.

Yet that trend has run into a reluctance among many Americans to sell their homes — and have legions of potential buyers parade through their living rooms — during the pandemic.

The number of available homes collapsed nearly one-third by February compared with a year earlier, to just over 1 million, according to the National Association of Realtors. Thatís the sharpest yearly drop on recor