#!/usr/bin/perl

use strict;
use warnings;

my $sum = my $count = 0;
while (<>) {
    for my $n ( split ) {
        $sum += $n;
        $count++;
    }
}
if ( $count ) {
    printf( "Average over %d values: %7.3\n",
            $count, $sum/$count );
} else {
    warn "No numeric data\n";
}