WASHINGTON (AP) — There was a 5.2% jump in Americans signing contracts to buy homes in January from the previous month as lower mortgage rates and a solid economy are pushing up demand for housing.

The National Association of Realtors said Thursday that its index of pending sales climbed to 108.8 last month. These contract signings — a barometer of finalized purchases over the next two months — have risen 5.7% over the past year.

Homebuyers have benefited from a steady drop over the past year in the average interest charged on a 30-year mortgage. This has improved affordability for buyers with sufficient savings. But sales growth might also be restricted by a historically low inventory of homes for sales and prices that climbing faster than wages.