This rating system makes a feable attempt to view collectibility on a global scale. Assumptions are made that you know how to use eBay sites that are foreign to you and deal successfully with sellers in other countries. Realize, that at any time you may stuble across a cache of rare games. This scale only considers what is generally available on eBay (and some other foreign auction services) over a large sample period.

    Not enough is known to accurately grade it.
    Oddity. You'll be very lucky to ever find this.
    Quite Rare. Might see one or two in a year.
    Appears 2 - 5 times a year.
    Appears 5 - 10 times a year.
    Appears 10 - 15 times a year.
    Appears 15 - 25 times a year.
    Appears a few times a month on auction.
    Probably off retail shelves but very common on auction.
    Can still be bought retail.