Denver’s population during the past five years surged 10 percent to about 700,000 as the fastest-growing major American city after Austin, Texas, overtaking Baltimore, Boston, Detroit and Washington as it climbed to No. 19 from No. 22 in 2010, according to data compiled Bloomberg. As the Denver population booms, the city’s and state’s unemployment rates remain among the lowest at 3.8 percent, more than a percentage point below the national average of 4.9 percent, according to Bloomberg data.

The DIA’s success helped put Denver at the top for U.S. homeowners with above-average growth and below-average price fluctuations. During the past 30 years, the housing market for Denver produced the second-best return after Portland, Oregon, adjusted for price swings of the 20 major cities in the U.S.,

Inflation-adjusted rents have risen by 64% since 1960, but real household incomes only increased by 18% during that same time period, according to an analysis of U.S. Census data released by Apartment List, a rental listing website.

Renters fared the worst during the decade between 2000 and 2010, when inflation-adjusted household incomes fell by 9%, while rents rose by 18%, according to Apartment List. That is likely because there were two recessions during that time and a housing bust in 2008 that drove millions of homeowners into renting.

Many well-off Americans own more than one home: The 2013 Survey of Consumer Finances from the Federal Reserve showed that just under 40% of respondents in the top 10 percentile of income owned at least one second home. World-wide, people with at least $30 million in assets have an average of 2.9 properties, according to a report published last year by global research firm Wealth-X and Sotheby’s International Realty. The world’s 2,479 billionaires have an average of four homes apiece.

As of mid-year 2016, metros with the best cap rates were Cleveland at 11.1 percent, Columbia, SC at 9.7 percent, Birmingham at 8.5 percent, and Pittsburgh and Milwaukee, both at 8.4 percent, according to HomeUnion Research Services. Meanwhile, the coastal markets of San Francisco, San Jose and Orange County had the lowest cap rates – between 2.4 percent and 3 percent.