Twin drum rollers 2014 2,249 h United States, Hannibal, Iowa
Single drum rollers 2018 4,079 h United States, Ottumwa, Iowa
Single drum rollers 2015 646 h United States, Des Moines, Iowa
Single drum rollers 2019 3,116 h United States, Des Moines, Iowa
Single drum rollers 2011 2,297 h United States, Ottumwa, Iowa
Single drum rollers 2020 1,529 h United States, Mason City, Iowa
Single drum rollers 2021 2,180 h United States, Postville, Iowa
Single drum rollers 2021 290 h United States, Cedar Rapids, Iowa