The article goes deeper than just 2016. Here's a quote:
"Lack of voter turnout is a problem in nearly every city, not just every four years, but every year in local elections. According to an analysis from Portland State University, turnout in the nation’s largest 30 cities is a dismal 20 percent of the voting age population."
I couldn't find much hard data, but most articles and data seemed to be of this general consensus