Fun with IMDb data (http://www.imdb.com/interfaces)

rating-reasons-count.sh

# Show ratings and reasons (e.g. "crude humor and language") along with the number of times they occur, e.g.:
#
#     270 R       violence and language
#      61 R       strong sexual content
#      58 PG-13   brief strong language
#     ... ...     ...


cat mpaa-ratings-reasons.list |
sed --quiet --regexp-extended '
  /^RE: rated/I !b                # Match or skip to end of script
  h                               # Copy pattern space to hold buffer
  n                               # Copy next line to pattern space
  s/^RE: //I; !t                  # Remove "RE: " from beginning or skip to end of script
  H                               # Append pattern to hold buffer
  x                               # Swap pattern space and hold buffer
  s/\n//                          # Remove newline
  s/^RE: rated (\S+) for /\1\t/I  # Replace e.g. "RE: rated PG-13 for " with "PG-13\t"
  p                               # Print result
' |
sort |
uniq --count --repeated |
sort --numeric-sort --reverse --key=1