Google Developers shared statistics: In 2019, Android users tried to install 1.9 billion malicious applications from outside the Google Play Store (for example, from third-party application stores). Moreover, in 2017 and 2018 years, this figure was at around 1.6 billion.
Google explains that this indicator is growing for two main reasons. Firstly, Play Protect every year better and better detects and blocks the malware. Secondly, more and more Android users install applications from outside the Play Store, that is, they use third-party sites and application stores (as a rule, due to the fact that official application stores are simply not available to them).
Let me remind you that Google Play Protect has existed since 2017 and is used to scan all applications already installed on the device (so that the updates do not bring the malware); Scan new applications installed from the Play Store scanning new applications installed from any third-party sources. Moreover, since 2018, Google Play Protect has been proactively scanning the Internet to search and index any APKs so that it can detect the malware before users.
In a recent report, Google analysts write that Play Protect currently scans over 100 billion Android apps per day. Moreover, it is expected that Play Protect's ability to detect malware will only increase in the future. In particular, this is due to the fact that in November 2019, Google, ESET, Lookout and Zimperium announced the creation of the App Defense Alliance, whose purpose, as the name implies, will be to identify malicious applications and protect users.