America’s housing market has grown so overheated as demand outpaces supply that prices keep hitting record highs — and roughly half of all US houses are now selling above their list price.

Two years ago, before the pandemic struck, just a quarter of homes were selling above the sellers’ asking price, according to data from the real estate brokerage Redfin.

On Tuesday, new data further illuminated the red-hot nature of the housing market: Prices rose in March at the fastest pace in more than seven years. The S&P CoreLogic Case-Shiller 20-city home price index jumped 13.3 percent that month compared with a year earlier — the biggest such gain since December 2013. That price surge followed a 12 percent year-over-year jump in February.

Several factors are driving the seemingly relentless rise in home prices. The pandemic has encouraged more people to seek out the additional space provided by a single-family home. Yet at the same time, COVID-19 discouraged many homeowners from selling and opening up their homes to would-be buyers, thereby shrinking the number of homes for sale.

And mortgage rates remain at historically low levels, with the average rate on a 30-year fixed mortgage around 3 percent. A year ago, the average was nearly 3.25 percent.