With help from a team of experts in statistics, graphics, and technology, R.W. Lewis (Ralph Winter's daughter), has brought the US Center for World Mission's original "Pie Chart" into the 21st century with updated statistics, clarity, and animation. Click here for a short animated version.
Joshua Project has downloadable powerpoints explaining the chart in
Read the full article by R.W. Lewis explaining this and other helpful charts, in the Winter/2018 issue of the International Journal of Frontier Missiology. This link also includes a graphic of the original chart by Ralph Winter, "Penetrating the Last Frontiers."