#!/usr/bin/perl
$sel = $ARGV[0];
shift @ARGV;
for (@ARGV) {
	$s = 0;
	$n = 0;
	open(FILE, $_) || die "$_: $!";
	while (<FILE>) {
		$c = 0 if /<TR>/;
		if (/<TD[^>]*>([0-9.]+)/ ) {
			$c++;
			next unless $c == $sel;
			$s += $1;
			$n++;
		}
	}
	close FILE;
	print "$s/$n = ", $s/$n, "\n";
}