We finally got some really good data on just how much money Google makes from YouTube and Google Play

One of the enduring mysteries about Google is exactly how it makes its money. The company books $17.2 billion a quarter in sales, but Google only discloses six facts about where those sales come from:

• Ad revenues from Google's own sites: $12 billion
• Ad revenues from Google Network Members' websites: $3.6 billion
• "Other" revenues: $1.7 billion
• Revenue from the US: 43%
• Revenue from the UK: 10%
• Revenue from the Rest of the World: 47%

Google's lack of transparency has been so frustrating that Morgan Stanley recently called on the company to break out more of its sales data, arguing that if investors could see how Google was growing the stock might be worth more.

Luckily, Credit Suisse analyst Stephen Ju and his team have been tracking Google revenue via the company's advertising clients.

Here is their estimate of revenues being generated by YouTube and Google Play:

The team believes YouTube and Google Play now form 15% of Google's revenues:

We believe the aggregated revenue contribution from YouTube AND Google Play has risen from 4% of Gross Revenue in 2010 to 15% in 2015 and should reach 24% by 2020, given the higher trajectory of growth versus core search. And as these businesses continue to scale, they should both see gross margin expansion which should underpin near-to-medium-term operating margin stabilization and eventually to margin expansion.

Credit Suisse then broke out YouTube's revenues alone, and predicts they might grow to $6 billion in 2015:

And here is Google Play, at about $5.1 billion for this year:

If you're interested in more guesswork about Google Play revenue then Andreessen Horowitz blogger Benedict Evans has a post and some charts here.