Before revision: Revised cathodic automotive electrocoat primer systems were introduced in the 1970s that markedly reduced the problem of corrosion experienced by a vast number of automobiles in the first seven decades of automobile manufacturing.
After revision: that had beenRevised cathodic automotive electrocoat primer systems were introduced in the 1970s that markedly reduced the problem of corrosion experienced by a vast number of automobiles in the first seven decades of automobile manufacturing.