This graph is telling us that: Voter turnout at the end of the 19th century declined because of the breakup of political machines. Remember that political machines, also known as Clientelism in Latin America, is the practice of giving gifts and rewards in exchange of votes. In other words, previous days before the election a group of politicians would "buy" people's votes by giving them money or other gifts. This was very common during the last 1800s and people stop voting because most of the elections were won by corrupt candidates.
