Code:

awk '{s[$2]=$0; c[$2]++} END {for (i in s) print s[i],c[i]}' *.tab

By indexing with field $2, a duplicate is overwritten in array s, and further increases the count in array c. Array s simply stores the whole line - it would save some memory to leave out the field $2.
At the end it prints all elements of array s (in a random order) together with the conter in array c (in the same order). The i variable is equal to the field $2 - not printed because s[i] is already the whole line.
For demonstration, here is a variant that consumes less memory but does not print field $3:

Code:

awk '{s[$2]=$1; c[$2]++} END {for (i in s) print s[i],i,c[i]}' *.tab