This is precursor to a data science question. Essentially, I am trying to map bitcoin's price to the number of wallets opened today on an exchange. It's quite common that the users would put in a buy request tomorrow, so a time series can be applied.
You won't be able to see the number of wallets, but you could get quite an idea by looking at the number of adresses an exchange generated.
( Exchanges such as poloniex only have 1 wallet for all their customers. )
I'm not entirely sure if walletexplorer also tracks coinbase adresses, but in the case it doesn't, you can use http://matbea.net
They currently track over (28.500.000+) coinbase adresses.
^^ (I wouldn't recommend using their webwallet though, and i'm also not saying that this is 100% indexing all adresses.)
For example, using matbea.net, i was able to identify 1DUiLkf34q7MVxtRkMAXVtP42UNGRrbftY as a coinbase adress.
No one ever creates Bitcoin wallets, they instead just use an empty one. The process of starting a new Bitcoin wallet is by cryptographically generating a private key. From the private key, you can derive a public key and a public address which you then distribute as the recipient of a potential Bitcoin transaction. These keys are generated randomly, so there is a chance, despite its minimal possibilities, that the key your wallet produced ends up the being the same key that someone is using today. This key could have funds that are spendable, and you just got access to the private key to their wallet. Now, the chances that someone ends up generating a private key that is, or was, being used at all is
Imagine every bitcoin private key was a grain of sand. There are, approximately,
2^63 grains of sand on earth. Now replace each grain of sand on earth with the earth itself, making there be
2^63 grains of sand in place of each grain of sand there already existed. Now, if you add up all this sand, you will have
2^126 grains of sand, which is still
2^160, being the total amount of possible addresses.
Now with all this information, try and find out which of these addresses Coinbase has chosen. It's impossible.