$cat test1
#!/bin/ksh
ls -l | grep "^-" | awk '{
key=$6$7
freq[key]++
}
END {
for (date in freq)
        printf "%s\t%d\n", date, freq[date]
}'

$ls -l | grep "^-"
-rw-r--r--    1 admin    other             0 Jul 30 12:31 test.cpp
-rw-r--r--    1 admin    other             3 Aug 16 07:56 test.cpp.z
-rw-r--r--    1 admin    other             0 Jul 30 12:31 test.txt
-rw-r--r--    1 admin    other             0 Jul 30 12:31 test1.cpp
-rw-r--r--    1 admin    other             3 Aug 16 07:56 test1.cpp.z

$./test1
Aug16   2
Jul30   3