With the exception of key dates (e.g., 1877), historically Indian Head cents have not performed quite as well as some other coins— large cents and other early coppers, for example. Currently, mint-state IHC's can be worth anywhere from around $100 for common dates on into the four-figure range for some of the scarcer varieties The latest Red Book lists the 1873 Doubled Liberty at $13K in MS-63.
Mintages are available in most standard references such as the Red Book; the highest year was 1863, with over 49.8 million.
One way to check trends is to compare older editions of price guides with recent ones, and of course guide prices with dealer price lists and catalogs— and especially actual prices paid. For the latter, although completed listings on eBay are okay, check prices realized in auctions by major numismatic firms such as Heritage and Stack's. You can access these (Heritage, anyway) by registering at their website.