Michigan saw its seventh straight year of population growth, according to U.S. Census Bureau estimates released Wednesday. Nearly 10 million people lived in the state on July 1, 2018 — an estimated 9,995,915 residents, up 0.2 percent from a year earlier.

Despite the increase, Michigan's growth rate lags behind the national rate. Nationwide, the population increased by 0.6 percent to 327.2 million in 2018.

Michigan's population peaked in 2004 at 10,055,315.

What factors are behind Michigan's slow but continued growth? For the third consecutive year, more people are moving to the state compared to those leaving, what researchers describe as positive net migration.

Births and deaths are also used to calculate population estimates but these numbers are less likely to shift dramatically over short time periods, according to the Census.

"In 2017 Michigan had the lowest number of births since 1945 and the highest number of deaths ever recorded," said demographer Kurt Metzger. "As natural increases drop, it becomes more important for Michigan to retain current and attract new residents."

Metzger expects that Michigan will surpass 10 million people by 2020, but will not exceed the 2004 estimate.

Nevada and Idaho had the fastest annual population growth at 2.1 percent.

Nine states experienced a population decline.

Population estimates are a good indicator of how many seats Michigan may hold in the U.S. House of Representatives after the next census in 2020. Michigan currently holds 14 of 435 seats.

Michigan may be gaining people, but based on current growth compared to other states, Michigan is expected to have 13 seats, losing one, according to the University of Michigan's Population Studies Center. The last time Michigan had 13 seats was in 1920.

Michigan had its highest number of House seats, 19, after the 1960 and 1970 censuses. Every decade since then, Michigan has lost at least one seat. In 1990 Michigan lost two seats.

Kristi Tanner is a reporter on the Free Press Investigations Team. Contact her at 313-222-8877 or ktanner@freepress.com.