“Landlords grow rich in their sleep,” philosopher John Stuart Mill once said. While that might be an exaggeration, the recent Freddie Mac report detailing a positive outlook for the U.S. multifamily market in 2020 demonstrates that it’s a good time to be a landlord.

To help investors researching properties from that perspective, investment property site RealtyHop recently released its January Property Investment Index detailing residential capitalization rates and net operating income across the 100 most populous real estate markets in the United States.

According to the report, the average cap rate across those cities was 4.03 percent, with Detroit having the highest at 14.61 percent and San Francisco the lowest at 1.83 percent. The average property tax rate of all cities was 1.14 percent.

Boston’s cap rate, at 3.59 percent, was below the national average of 4.03 percent, meaning it’s slightly more difficult to make a profit here on rentals than in some other areas of the country. Coming in at No. 61 on the list, Boston’s median home price was $677,250, aggregated yearly rent $35,976 and maintenance costs $6,773. Boston’s property tax rate, at 0.73 percent, was below the national average of 1.09 percent. Net operating income for landlords was estimated at $24,284.