What kind of photos are selling?

Probably one of the most important things for selling photographs is actually having the kind of photos people are interested in. I am wondering where any of this kind of industry information may be available? Granted if you are a wildlife photographer and you learn that photos of cell phones are popular it may not help you much, but if you learn that certain animal photos are much more in demand than others then this information could make a substantial difference to your sales.

I can already hear the artists groaning. I'm guessing that some will feel that this is not in the spirit of "art". Well, that may be true but if you have a web presence you are likely trying to earn some money at the same time as being an artist. Approaching this strategically can be a good idea - provided one doesn't feel too compromised I suppose.

I have recently posted breadfruit photos and sugar cane photos and the like on my site. I think that these are an example of putting up what one has but not necessarily putting up what the market is looking for. It is great for the site to have alot of breadth. I'm happy if people can find all manner of photos but at the same time I really should be focusing my limited time on photos that have the most selling potential. If I had unlimited resources then putting up all manner of photos wouldn't hurt but I don't have unlimited resources. As such I have to focus on "the low hanging fruit" - a lesson that was beaten into my during my 8 year stint in ecommerce (I'm sure there are quite a few other lessons that didn't sink in but that's another story). Seems I need to start practicing what I preach.

The gist of this ramble/discussion is if you know what photos sell, and if you are sales focused, then take those photos and get them up on your site. Not exactly rocket science. However, where can one get this information? I'm sure the big boy stock photo agencies have all sorts of metrics for their sites and business but I suspect they don't publish the information - or maybe they do? If photographers know what to shoot and agencies are better able to sell these photos then perhaps this information is in the public domain? If it is can someone please let me (and probably quite a few others) know where and how to access such information?