This is a double edged sword, because while there might be fewer Android exploits discovered per year, the number of publicly-known and exploitable vulnerabilities in circulation at any given time is almost certainly lower on iOS, where most users have updated to the latest version within two weeks of its release, than on any device in the fragmented Android ecosystem, where only users of devices from proactive vendors even have the option to update their device to the latest version with upstream security patches. And that's assuming their device isn't EOL, which tends to happen more quickly to Android devices than Apple devices, despite the latter's reputation for planned obsolescence.