Rail Industry Question

Does anyone know approximately how many rail cars are in use in North America?

As a follow up, what percentage of that can I assume is decomissioned each year?

Thanks for any help you can give!

Well, first here's the BTS count of railcars (and most other forms of vehicles) in the US by year, up to 2004 (latest figures they have) BTS table

Note that Class I railroads' car counts are trending down, while private car shippers are trending up (and the crossover in ownership percentage, which apparently occured in the 1990s).

Next, try this Link for a discussion on various companies scrapping railcars, and the number they average per year.

I know these values are floating around somewhere, but those two links can get you started.