America’s biggest cities are continuing to outgrow their suburbs as the economy’s plodding recovery makes it harder for city dwellers to move to greener pastures.

The nation’s 51 largest metropolitan areas — those with populations over one million — saw their city populations grow 1.12% between July 2011 and July 2012, up from 1.03% a year earlier and an average of 0.42% between 2000 and 2010, according to an analysis of Census data by demographer William Frey of the Brookings Institution in Washington. By contrast, these cities’ suburbs grew just 0.97% last year, higher than 2011’s 0.96% but far below the average of 1.38% in the previous decade. In the New York-Northern New Jersey metro area, New York City — the nation’s largest, with over 8 million people — saw its population grow 0.8% between July 2011 and July 2012, much faster than the 0.3% growth of its suburbs. Between 2000 and 2010, the New York metro area’s suburbs generally grew faster than New York City.

Fewer people “are moving out of the big urban cores because the recession [and sluggish recovery have] tended to freeze people in place,” says Kenneth Johnson, senior demographer at the Carsey Institute and a sociology professor at the University of New Hampshire. The Chicago metro area exemplifies the trend: Chicago’s population grew 0.4% between July 2011 and July 2012, while its suburbs grew only 0.2%. In the 2000s, Chicago’s population dropped 0.5% on average, while its suburbs gained 0.9%.