Dec. 19 (UPI) -- U.S. population growth slowed to the lowest level in decades last year, according to data released Wednesday by the U.S. Census Bureau.
Population growth slowed to 0.6 percent between July 1, 2017, and July 1, 2018, from a 0.72 percent increase between July 1, 2016, and July 1, 2017, amid rising death rates and falling birth rates throughout the year.
"Many states have seen fewer births and more deaths in recent years," Sandra Johnson, a demographer/statistician in the Population Division of the Census Bureau, said. "If those states are not gaining from either domestic or international migration they will experience either low population growth or outright decline."
Natural increase -- the excess of births over deaths -- was 1.04 million last year, with 3,855,500 births and 2,814,013 deaths, down from 1.1 million the previous year.
"With fewer births in recent years and the number of deaths increasing, natural increase has declined steadily over the past decade. In 2008, natural increase was nearly 1.8 million," the Census Bureau said.
However, international migration rose to 978,826 last year compared to 953,233 the year before, as U.S. population continues to grow as a whole.
New York and Illinois saw the greatest decreases in population falling by 48,150 and 45,116 people, respectively. West Virginia, Louisiana, Hawaii, Mississippi, Alaska, Connecticut and Wyoming also all saw declines of between 11,000 and 1,000 people.
Hurricane Maria accelerated a downward trend in Puerto Rico's population, as the U.S Commonwealth lost 129,848 people, or 3.9 percent of its population, last year.
"Puerto Rico has seen a steady decline in population over the last decade," said Johnson. "Hurricane Maria in September of 2017 further impacted that loss, both before and during the recovery period."
The decrease over that 10-year span has primarily been due to higher rates of out-migration over in-migration and natural increase as it total population has fallen from 3,726,157 in 2010 to 3,195,153 in 2018.
Nevada and Idaho were the fastest-growing states in the country, as both their populations increased by 2.1 percent, followed by Utah at 1.9 percent, Arizona at 1.7 percent and Florida and Washington both at 1.5 percent.
The population of Washington, D.C., also surpassed 700,000 people for the first time since 1975 at 702,455.
"The change is due primarily to an influx of people from other parts of the country that began early in the decade. While the increase has begun to slow, the District of Columbia still grew by almost 1 percent last year," the Census Bureau said.