#!/usr/bin/env perl

use Data::Dumper;                                          # I like to dump stuff
use strict;                                                # "strict" and "warnings" are a best practice
use warnings;

my %encountered;                                           # We're going to "stuff" the numbers encountered here
while (<DATA>) {
    chomp;
    while (m{(\d+)}g) {                                    # Find numbers in the string one set (2019) at a time
        push @{$encountered{$1}},$_;                       # Note 1 will occur twice in the line "1 this year is 2019 1"
        };
    };

# Dump them with a label (and file and line number) so we can verify
warn Data::Dumper->Dump([\%encountered],[qw(*encountered)]),' ';

# Print them longest first
local $"=qq{', '}; #"                                      # To make them more readable
for my $number (sort {$b <=> $a} keys %encountered) {      # Sort largest number first
    print "$number: '@{$encountered{$number}}'\n";
    };

__END__
Hello, i'm 18
1 this year is 2019 1
1 2 3 - 4