Wisconsin ranks among top states people are leaving. (WBAY, 1/19/20016)
In 2015, Wisconsin ranked seventh among states that lost the most residents to another state, based on percentage, according to a study by Atlas Van Lines moving company that looked at where people were moving.
Illinois ranks 3rd; Indiana 6th.
The inbound and outbound drops from 2008 to 2009 probably have much to do with the Great Recession, the result of a bottoming out of the housing market.
As for the steady increase in out-migration since 2012, I'll leave you to speculate.