grp$ improve freq
 M     1       3
 M     2       4
 M     3       7
 M     4       3
 M     5       2
 M     6       1
 M     7       0
 M     8       0
 M     9       0
 M    10       0
 P     1       0
 P     2       2
 P     3       5
 P     4       3
 P     5       8
 P     6       4
 P     7       2
 P     8       1
 P     9       1
 P    10       0