By most estimates, the Chicago area's population will continue to decline in the coming years. Over the past year, the Tribune surveyed dozens of former residents who've packed up in recent years and they cited a variety of reasons: high taxes, the state budget stalemate, crime, the unemployment rate and weather. Census data released Thursday suggests the root of the problem is in the city of Chicago and Cook County: The county in 2016 had the largest loss of any county nationwide, losing 21,324 residents.