GameSpot reports that over 18 million people subscribe to Xbox Game Pass.
Xbox Cloud Gaming (formerly xCloud), still in beta, is available exclusively for the Xbox Game Pass Ultimate subscription plan. Microsoft did not specify how many subscribers belong to Game Pass Ultimate specifically.
Game Pass Ultimate is currently available for $14.99/month. The first three months of a subscription, however, cost only $1/month. Game Pass Ultimate also includes full access to Xbox Live Gold and EA Play (formerly Access).