Do CRAN packages that depend on the stats package use a copyleft license?

gpl-stats.R

#!/usr/bin/env Rscript

# Do CRAN packages that depend on the stats package use a copyleft license?
# https://twitter.com/cimentadaj/status/1154420408508043264

Sys.Date()
## [1] "2019-07-26"

library(stringr)

x <- as.data.frame(available.packages(), stringsAsFactors = FALSE)
x$copyleft <- str_detect(x$License, "GPL") |
              str_detect(x$License, "General Public License")
mean(x$copyleft)
## [1] 0.8170245
table(x$copyleft)
##
## FALSE  TRUE
## 2659 11873

x$Depends <- ifelse(is.na(x$Depends), "", x$Depends)
x$Imports <- ifelse(is.na(x$Imports), "", x$Imports)
x$Suggests <- ifelse(is.na(x$Suggests), "", x$Suggests)

x$stats <- str_detect(x$Depends, "\\bstats\\b") |
           str_detect(x$Imports, "\\bstats\\b") |
           str_detect(x$Suggests, "\\bstats\\b")
mean(x$stats, na.rm = TRUE)
## [1] 0.2580512
table(x$stats, useNA = "ifany")
##
## FALSE  TRUE
## 10782  3750
table(x$copyleft, x$stats, dnn = c("copyleft", "stats"))
## stats
## copyleft FALSE TRUE
## FALSE  2160  499
## TRUE   8622 3251
sum(!x$copyleft & x$stats) / sum(x$stats)
## [1] 0.1330667
x[!x$copyleft & x$stats, c("Package", "License")][1:5, ]
## Package            License
## ABCoptim   ABCoptim MIT + file LICENSE
## acmeR         acmeR MIT + file LICENSE
## AGread       AGread MIT + file LICENSE
## ahpsurvey ahpsurvey MIT + file LICENSE
## airr           airr          CC BY 4.0