can you just say how many private keys do you have to the same address? And also how many addresses do you have with more than one private key?
we are not "mapping" keys to addresses to have 1:X ratio. we are hashing the public key which returns a random result so there is no fixed ratio. there is a chance of collision because the hash size (160 bits) is smaller than the number of private keys (a little less than 256 bit) but so far nobody has found any collisions and will not find any for a very long time. anybody who claims otherwise without proof is most probably lying.