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library(mxmaps)
library(viridis)
library(scales)

df_mxmunicipio$value <-  df_mxmunicipio$indigenous / df_mxmunicipio$pop 
gg = MXMunicipioChoropleth$new(df_mxmunicipio)
gg$title <- "Percentage of the population that self-identifies as indigenous"
gg$set_num_colors(1)
gg$ggplot_scale <- scale_fill_viridis("percent", labels = percent)
gg$render()