I know that all of them apply but what is the actual percentage of those organizations that get grants?

Many more organizations apply for open grants than get them, but as far as I know, there is no agency that counts all the applications, records the number of failed applications, and publishes such statistics. The organizations that failed aren't likely to make that information public either. You can try to see if such stats are available at http://www.grants.gov or http://www.fedstats.org but I doubt the information is available.