There are a total of almost 425 million STORJ tokens in existence. 245.0 M STORJ are now in rolling time locked contracts. The current approximate circulating supply can be found on CoinMarketCap. You can find more details about the token sale here.
You can read the blog post An Overview of Tokens Uses, Flows and Policies at Storj Labs for details how they are used.
You can read the blog post about balances and flows report STORJ Token Balances and Flows Report: Q3 2020.