a lot has to do with geography and what has been common in that area for games and not so common. i find too there seems to be this pinball game bandwagon that goes on not sure if its from sites or gatherings but a title seems to get on everyones "a" list for whatever and possibly several reasons and the prices seem to soar, then that popularity wanes with the next "a" game that comes along.. im only going by my perspective regionally (ontario) and i seem to think 60 Gottliebs have been trending downward. they are very difficult to sell. i think their popularity lies in the restoration for these beauties and very few projects can be found , and those that have been restored, most dont see the value , expense and time put into them. id say 70s gottliebs (and im speaking in general) have been having the greatest uprise in pricing . those with nice collections of SS and dmd always seem to want a 70s gottlieb in their collection. id like to think most 70s williams/ballys have stayed rather status quo unless its one of the few titles like old chicago/4mbc etc. i dont see many 60s ballys but any i have have been cheap . id love to see more 60s williams but there too it only seems to be the more talked about titles ie heatwave that command the most. id also think there has been a rise in woodrail prices over the last two years or so , but that too because they are more rarely seen on the market. Again , i dont have empirical data to substantiate but do keep a keen eye on most public sales of games.

Also one thing i used to do is check different mr pinball price guides for trends. for instance ive seen majorettes rise then fall then rise again. i dont know what they use for their sources to gauge increase or decrease their value i suppose this rather large upswing in pinball popularity isnt really measured in those price guides however.