Births have fallen significantly in 2017 despite the improving economy, according to a new projection released Monday.

Demographic Intelligence, a firm that forecasts demographic trends for companies, projected Monday total births will fall 2.8 percent in 2017 from 3.95 million to 3.84 million.

That would bring the total fertility rate down to 1.77 children per woman, the lowest level in three decades. The total fertility rate, thought to be a highly valuable single metric of a country’s fertility, fell to 1.82 in 2016, according to provisional data released by the National Center for Health Statistics in June.

What makes the decline in births particularly surprising is that it comes even as the economy has improved significantly in recent years, with the unemployment rate falling in 2017 to levels not seen since the dotcom-bubble year of 200. Births cratered during the recession as joblessness or reduced pay forced people to postpone major life decisions, but have not since bounced back as demographers expected.

Total fertility climbed in each of the last three economic recoveries after falling during a recession.

"This decline in births is especially striking because most observers, including the U.S. Census, anticipated that a growing population of young people and a stronger economy would lead to a rise in births; but we are seeing just the opposite: a big decline in births,” said Sam Sturgeon, Demographic Intelligence’s president.

Sturgeon suggested the drop off might be chalked up to a loss of interest in committed relationships on the part of younger people that in turn might be related to the increased use of social media, smartphones, and other technologies that are still new.

For years, both teen and young adult childbearing have been falling. The birthrate for teenagers declined by more than half between 2007 and 2016, according to the National Center for Health Statistics, while birth rates for women in their 20s have fallen more gently in recent years.

Part of those declines is a function of young people having less sex. Between 2010 and 2012, more than 90 percent of young adults, those between ages 18 and 25, reported having sex within the last year. By 2014, that figure was 78 percent.