Simple Perl program to count the number of month-day-weekday combinations since 1538 CE.

date-stats.pl

#! /usr/bin/env perl                                                            
use Modern::Perl '2015';

use DateTime;
###                                                                             
use utf8;
binmode(STDOUT, ':encoding(UTF-8)');

my $date = DateTime->new(year=>1583 , month=>1 ,day=>1);
my $stats;
say "collating...";
while ($date <= DateTime->now()) {
    push @{$stats->{$date->month}->{$date->day}->{$date->day_of_week}}, $date->\
year;
    $date->add(days=>1);
    say $date->ymd if ($date->year % 25 == 0 and $date->month==1 and $date->day\
==1);
}
say "printing...";
for my $month (sort {$a<=>$b} keys %{$stats}) {
    for my $day (sort {$a<=>$b} keys %{$stats->{$month}}) {
        printf "%02d-%02d: ",$month,$day;
        for my $wday (sort {$a<=>$b} keys %{$stats->{$month}{$day}}) {
            printf "%02d ", scalar @{$stats->{$month}{$day}{$wday}};
        }
        print "\n";
    }
}

Inspired by https://boston.conman.org//2023/01/08.1 via https://lobste.rs/s/a4m4al/today_s_date_happens_more_frequently_on