In the United States, in the mid-1990s, malls were still being constructed at a rate of 140 a year. But in 2001, a PricewaterhouseCoopers study found that underperforming and vacant malls, known as "greyfield" and "dead mall" estates, were an emerging problem. In 2007, a year before the Great Recession, no new malls were built in America, for the first time in 50 years. City Creek Center Mall in Salt Lake City, which opened in March 2012, was the first to be built since the recession.