Portland's population has been and remains predominantly white. In 1940, whites were over 98% of the city's population. In 2009, Portland had the fifth-highest percentage of white residents among the 40 largest U.S. metropolitan areas. A 2007 survey of the 40 largest cities in the U.S. concluded Portland's urban core has the highest percentage of white residents. Some scholars have noted the Pacific Northwest as a whole is "one of the last Caucasian bastions of the United States". While Portland's diversity was historically comparable to metro Seattle and Salt Lake City, those areas grew more diverse in the late 1990s and 2000s. Portland not only remains white, but migration to Portland is disproportionately white.