Good point. If i only had a brain! I'm going to have to think on that one. All I can come up with now, taking into consideration the fluctuation of money values all over the world, is that to include all those countries would be insurmountable. i would think that buyers in other countries are used to translating American prices into local currency, and adjusting for taxes, shipping, etc. Good question.
Once musical instruments become collectible, they usually attain higher values in a certain circle of collectibility. For instance, I would think that Premier drums command much more interest in Britain ,than in North America. Cars are pretty much locked into a market situation, in a specific country,state or in my case province, due to import restrictions based on safety equipment,transport dept. standards etc., so a BB works within that confined market. How do you propose to accomodate the fact that drums have international fluidity ,can move across borders pretty easily and all of a sudden a Capelle snaredrum has lost 1/2 it's value ,according to a book because it ended up in Nebraska?