use strict;
use warnings;
use Data::Dumper;
my $info;

{
local $/ = undef;
$info = <DATA>;
}

my %lines;

while ($info =~ m/(\d+)\: (.+?)\n(?=\d)/gs) {
    $lines{$1} = $2;
}

print Dumper (%lines);

__DATA__
3: Tag <test> found
Tag <test> found
5: Tag <test> found
7: Tag <test> found
14: Tag <test> found
16: Tag <test> found
18: Tag <test> found
21: Tag <test> found
25: Tag <test> found
27: Tag <test> found
29: Tag <test> found
32: Tag <test> found
34: Tag <test> found
49: Tag <test> found
80: Tag <test> found
98: Tag <test> found
Tag <test> found