A new report from Liftoff seeks to trace user acquisition trends in recent mobile game history, something that potentially offers developers a peek at the ebbs and flows of spending habits in the mobile games space. 

The report, which can be downloaded for free from the organization’s website, says this year’s numbers show that 13.4 percent of mobile game players complete an in-app purchase, which is a 67 percent increase in in-app purchasers from last year’s findings. 

Liftoff continues on to note that, despite rising engagement, the cost of IAP-completing user acquisition is actually down from last year’s numbers. In 2017, the company found the cost of picking up one of those free-to-play spenders was $50.69. This year, that number is down to $28.05. 

The report goes on to dig into the differences between spending trends on iOS and Android, noting iOS typically comes with higher user acquisition costs, but that those higher costs come with higher in-app purchase conversion rates, 21 percent compared to Android’s 10.8 percent. 

The data here comes from Liftoff’s own internal numbers, collected between June 1, 2017 and May 31, 2018. The company says that around 47 billion impressions and 15 million installs factor into the report’s final numbers, and all in all 350 games and their marketing campaigns were analyzed.

Developers can check out the full report for more insights from Liftoff, including month-by-month breakdowns of user acquisition cost trends, a look at how different genres typically fare in the top grossing lists, and info on how region and gender play into in-app purchasing habits.