Adams County nearly doubled its household growth from last year's 2,025 to 3,825 new households in 1999. Denver and Jefferson counties continue their positions as the region's largest counties for households with 225,300 and 209,200, respectively. Gilpin County's households grew by 100, while Clear Creek County's households grew by 25. In making the population estimates, the council of governments calculates the two components of growth, natural increase and net migration. Net migration is the number of people moving into the region minus those moving out of the region.
Natural increase is the number of births minus the number of deaths.
Because natural increase tends to be a relatively stable component of growth, the major variation from year to year in regional growth patterns is the level of net migration. Table 3 catalogs the region's births, deaths, natural increase, and net migration from 1990-2000. While it was net migration that fueled the Denver metro area's population growth in 1999, there was a slight decline in net migration. Net migration through the decade of the '90s played a large role in the region's growth, accounting for 59 percent of the region's total population gain. Douglas County, with a 93,144-person gain, accounted for 34.5 percent of the region's total net migration.