The state of Iowa Data Center has released the 2012 city population estimates. It is estimated that Pella has approximately 10,400 residents, Knoxville 7,300, Pleasantville 1,700, and Monroe 1,800. Marion County has a total estimated population of 33,400. For a complete list of population estimates for Marion County’s communities, and the rest of Iowa as well, visit www.iowadatacenter.org.