percent of the residents of the building qualify as low income, energy efficiency improvements like those available through Mass Save are available. Residential structures operated by non-profit organizations, for profit operations, or housing authorities may take advantage of these programs. In late 2020, the Baker Administration released a Decarbonization Roadmap that aims for net-zero greenhouse gas emissions by 2050. The plan calls for major investments in offshore wind and solar energy and would require all new automobiles sold to be zero-emissions (electric or hydrogen powered) by 2035. Demographics At the 2020 U.S. census, Massachusetts had a population of over 7 million, a 7.4% increase since the 2010 United States census. As of 2015, Massachusetts was estimated to be the third-most densely populated U.S. state, with 871.0 people per square mile, behind New Jersey and Rhode Island. In 2014, Massachusetts had 1,011,811 foreign-born residents or 15% of the population. As of July 2021, the population is estimated to have fallen to 6.98 million. Most Bay State residents live within the Boston metropolitan area, also known as Greater Boston, which includes Boston and its proximate surroundings but also extending to Greater Lowell and to Worcester. The Springfield metropolitan area, also known as Greater Springfield, is also a major center of population. Demographically, the center of population of Massachusetts is located in the town of Natick. Like the rest of the Northeastern United States, the population of Massachusetts has continued to grow in the late 20th and early 21st centuries. Massachusetts is the fastest-growing state in New England and the 25th fastest-growing state in the United States. Population growth was largely due to a relatively high quality of life and a large higher education system in the state. Foreign immigration is also a factor in the state's population growth, causing the state's population to continue to grow as of the 2010 census (particularly in Massachusetts gateway cities where costs of living are lower). 40% of foreign immigrants were from Central or South America, according to a 2005 Census Bureau study, with many of the remainder from Asia. Many residents who have settled in Greater Springfield claim Puerto Rican descent. Many areas of Massachusetts showed relatively stable population trends between 2000 and 2010. Exurban Boston and coastal areas grew the most rapidly, while Berkshire County in far Western Massachusetts and Barnstable County on Cape Cod were the only counties to lose population as of