|The 18-24 crowd spends more time, but the 25-34 crowd spends 3x the money.|
The data was gathered from a sample of iOS and Android freemium games with over 20 million users across more than 1.4 billion sessions, so I think most people would agree that's a statistically significant sample to look at.
From the chart you can see that game usage skews heavily towards the younger audience, which shouldn't surprise anyone. I'd also guess that smartphone usage tends to follow a similar distribution, with the over 55 crowd being the least likely to even have a smartphone, much less play a game on it. However, the money is definitely coming from the older audience; teens don't spend much at all on freemium games even though they play a lot of them. The real pot of gold lies with the 25-34 age range (spending nearly half the money) and with the 35-54 group (spending more than a quarter of the money). If your game targets those older spenders, you could make more money with fewer overall downloads.
This is important data as you consider the design of your game, the style of the artwork, and the marketing. If you're interesting in maximizing your returns, you need to consider the realities of the marketplace.