#!usr/bin/perl -w
use strict;

my %date_hash;

my @data = qw(
	NCLEGEND-11-20
	NCLEGEND-11-20
	NCLEGEND-11-2
	NCLEGEND-1-10
	NCLEGEND-1-10
	NCLEGEND-1-10
	NCLEGEND-1-20
	NCLEGEND-1-20);

foreach my $line (@data)
{
   chomp ($line);    #needed if @data is a file handle
   $line =~ s/-(\d)-/-0$1-/; #add leading zero for month
   $line =~ s/-(\d)$/-0$1/;  #add leading zero for date

   my $date = ($line =~ m/NCLEGEND\-([\d-]+)/)[0]; #get the "num" part
   
   $date_hash{$date}++;
}

foreach my $date (sort keys %date_hash)
{
    print "$date   $date_hash{$date}\n";
    #just print "$date\n"; if no need for counter value
}

__END__
Prints:
01-10   3
01-20   2
11-02   1
11-20   2