I'm sure "before:2015" or "before:2010" will improve them even more if you are only judging based on quality, but I'd wager almost everyone using the site wants

I'm sure "before:2015" or "before:2010" will improve them even more if you are only judging based on quality, but I'd wager almost everyone using the site wants up-to-date results, so this kinda defeats the purpose.