The numbers, based on data compiled by CVE Details mean that last year the odds favored that Android powered devices would be hacked more than any other mobile iOS. A vulnerability is a flaw in the OS that a hacker could use to make a device (like a smartphone) do things that it is not supposed to do. That would include release information to hackers such as contacts, text messages, calls, IMEI numbers, passwords, access to apps and more.
Also in the top 50 last year was Apple's watchOS, used on the Apple Watch. The smartwatch's operating system ranked number 35 with 77 vulnerabilities.
source: CVEDetails via BusinessInsider