I manually did a few cities in Hudson County for 2010 based off this:
http://www.citypopulation.de/php/usa...bridgeport.php
Guttenberg: 59,344 ppsm (pop 11,176)
West New York: 55,979 ppsm (pop 49,708)
Union City: 55,168 ppsm (pop 66,455)
Hoboken: 46,236 ppsm (pop 50,005)
Weehawken: 29,600 ppsm (pop 12,554)
That means the increase in weighted density in Hoboken was smaller than the increase in population. Looking at where most of the growth seems to have occured, it's around the Waterfront and Northwest of the city. These areas probably had little population and therefore little impact on the weighted density in 2000, and they are now around the density of the Hoboken average.