ANNAPOLIS, Md. (AP) _ Companies that make prescription opioid painkillers and allied groups have hired an average of 31 lobbyists in Maryland each year and given more than $227,000 to Maryland state lawmakers since 2006.

A joint investigation by The Associated Press and the Center for Public Integrity found that the organizations spent $880 million and hired an annual average of 1,350 lobbyists in state capitals around the country from 2006 through 2015.

The organizations’ lobbying in Maryland ranked 11th when drug makers’ lobbying hires are considered using a ratio factoring in all lobbyist registrations in each state.

The groups’ campaign contributions in Maryland ranked 39th in the nation using a ratio of all campaign contributions in each state.