By the Numbers

Estimated global population in 1946: 2.4 billion (U.S. Census Bureau)

Global population in 2021: 7.7 billion (U.S. Census Bureau)

Percent of global population currently living in urban areas: 56.2 (World Economic Forum)

People living in informal settlements: 1 billion (United Nations)

Percent of urban residents in 78 countries who had convenient access to public transit in 2018: 53 (United Nations)

Percent who lived within a quarter-mile of a park or open space: 31 (United Nations)

Approximate percent of U.S. urban land occupied by parks and open space: 15 (Land Lines)

U.S. urban residents who lacked access to a park within a 10-minute walk from home in 2020: 100 million (Trust for Public Land)

Total area, in acres, of vacant lots 0.5 acres or larger in the 25 largest U.S. urban cores: 580 (Property Shark)

Gallons of stormwater absorbed during rain events by Milwaukee’s 0.6-acre Fondy Park, a former vacant lot: 83,000 (City of Milwaukee)

Percent of surface area in Shenzhen, China, covered by green infrastructure: 24 (Land Lines)

Estimated amount spent per year on green infrastructure around the world: $25 billion (Land Lines)

Land value lost by flood-prone properties in Miami since 2005: $125 million (Land Lines)

U.S. coastal properties at risk of a 100-year flood, according to current FEMA maps: 8.6 million (New York Times)

Properties that actually face that risk when sea level rise is factored in: 14.6 million (New York Times)

Impervious surfaces added to the Houston metro area from 1997 to 2016, in football fields: 186,873 (Rice/Kinder Institute for Urban Research)

Total parking spaces in Seattle/parking spaces per household: 1.6 million/5.2 (Research Institute for Housing America)

Total parking spaces in Des Moines, Iowa/parking spaces per household: 1.6 million/19.4 (Research Institute for Housing America)

Acres of land owned by Bay Area Rapid Transit (BART) in San Francisco: 250 (BART)

Target number of housing units BART will produce on that land by 2040: 20,000 (BART)

Percent of those units that will be affordable: 35 (BART)

Housing units created if land near Greater Boston’s transit stations averaged 10 units per acre instead of 6.6: 243,000 (Massachusetts Housing Partnership)*

Combined population of U.S. legacy cities: 17 million (Legacy Cities Initiative)

Collective economy of U.S. legacy cities, in USD: $430 billion (Legacy Cities Initiative)

Property tax as a percent of U.S. local government general revenue in 2017: 30 (U.S. Census Bureau)

Property tax as a percent of total U.S. tax revenue in 2017: 10.6 percent (Urban-Brookings Tax Policy Center)

Total proceeds from the sale of building rights certificates (CEPACs) in São Paulo since 2004, in USD: $3 billion (Lincoln Institute)

Estimated percent of U.S. jurisdictions that charge impact fees to developers: 25 (Lincoln Institute)

Millions of acres conserved by land trusts in the United States: 56 (Land Trust Alliance)

Percent decrease in water treatment costs per 10 percent increase in forest cover in a watershed: 20 (American Forests)

Percent of Colorado River flow at risk in the next 30 years due to climate change: 20 (Colorado State University)

Percent of planners who say they are not involved enough in water planning and decisions: 75 (American Planning Association)

Vacant homes and apartments in 1950 as a percent of U.S. housing stock: 1 (Lincoln Institute)

As a percent of U.S. housing stock in the third quarter of 2020: 10.1 (U.S. Census Bureau)

Vacant housing units in the United States in the third quarter of 2020: 14.2 million (Federal Reserve Bank of St. Louis)

People experiencing homelessness in the United States during the most recent annual one-night count: 567,715 (U.S. Department of Housing and Urban Development)

Percent of U.S. renters who spent more than half their income on rent in 2018: 25 (Harvard Joint Center for Housing Studies)

Units of affordable housing created in Cambridge, Massachusetts, through inclusionary zoning: 1,000 (Lincoln Institute)

Inclusionary housing programs in the United States: 1,379 (Grounded Solutions Network)

Land banks in the United States: 200+ (Land Lines)

Distressed properties returned to the tax rolls by Ohio’s Cuyahoga Land Bank, 2009-2019: 11,436 (Cuyahoga Land Bank)

Estimated economic impact for every dollar spent by the land bank during that period: $8 (Cuyahoga Land Bank)

Total estimated economic impact of the land bank during that period: $1.43 billion (Cuyahoga Land Bank)

Contributors: Anthony Flint, Katharine Wroth, Emma Zehner, and Sarah Zobel.

* In the January/April 2021 print issue of Land Lines, this item cites earlier figures from the Massachusetts Housing Partnership, which originally used an average density of 6.4 to create an estimate of 253,000 new housing units. These figures were revised in January 2021.