As Berg notes, the new figures [PDF] released by the Census Bureau show that across America downtown populations grew significantly between 2000 and 2010. "Together, the total metro population living within four miles of city hall is more than 54 million – almost 21 percent of America's metro population. That's 17.5 percent of the national population living within a quick car ride, 30-minute bike ride or hour-long walk of the center of a big city," writes Berg.
The downtown growth has not been consistent across all metro areas, however, with larger metro areas showing a higher growth rate. "[T]those with populations of 5 million or more, saw a collective growth rate of more than 13 percent in the areas within two miles of city hall," reports Berg. While, "Metros with fewer than 2.5 million people saw only modest increases (0.2 percent for the 500,000 to 999,999 group) or even decreases (-1.2 percent for the 1 million to 2.499 million group)."
It's worth noting that the notable downtown growth did not preclude the expansion of the country's suburban and exurban areas as population centers. "And that's especially true in the largest metropolitan areas," writes Berg. "While the close-in areas in these metros' downtown saw double-digit growth between 2000 and 2010, so did areas 30 miles and beyond."