CASPER, Wyo. (AP) — Wyoming's population has dropped for the second year in a row. The Casper Star-Tribune reports that U.S. Census data released on Wednesday show the state has lost more than 6,600 residents since the energy bust began in 2015. About 6,000 of those residents were lost between July 2016 and July 2017. Wenlin Liu, chief economist at the Economic Analysis Division, says healthy economies in neighboring states like Idaho and Colorado are impacting whether Wyoming residents stay or leave. Idaho had the largest population increase in the nation last year at 2.2 percent. Colorado had the eighth-largest population increase. Wyoming's population decrease was 1 percent. That's the largest decline in Wyoming since 1989.