Newly released county population estimates show significant growth in Montana's northeastern oil patch.  That's according to the U.S. Census Bureau figures and The University of Montana Bureau of Business and Economic Research, which sent us the information. Now, that news is not going to knock you over with a feather, but what does stand out is just how much growth there was. Richland County which contains Sidney, was among the fastest growing counties in the country with estimated growth of 6.6 percent during the past year. True, that kind of growth only represents about 670 people given the sparse population to begin with, but you have to believe the trend will continue. For the sake of local scorecard holders, Missoula County's 2012 population is now estimated to be at 110,977 (up 0.8% from 2011), second only to Yellowstone County's 151,882. Ravalli County now checks in at 40,617.    DB