You're link appears to be broken, but I found it through google.
I'm not surprised the company trying to sell you antivirus protection is shouting from the top of the mountains that you need it. I also have some issues with how they classify malware. Many android apps are free. They use advertisements to get revenue. How do they increase that revenue? Targeted ads. It appears that trend is including apps that use your location or other data in the "malicious apps". Also notice, they didnt publish an app list. They want you to download the app to be protected.
1 in 10 apps =/= 1 in 10 popular apps that people actually use. IF there are that many malware apps, its going to be obscure apps that nobody uses
Common sense (dont download pirated apps) and precautions (such as reading reviews, looking at download counts and checking permissions) about what you're doing is more than enough to keep you malware free.
Edit:
Just thought of 1 more....Trend Micro is also pretty consistently listed near the bottom of most websites rankings of "top AV" companies. I'm going to chalk many of those up to false positives