Technology has advanced significantly and OS versions seem to be released at a faster and faster pace and it just occurred to me that iOS is on the same version number as the last classic (non-NEXTSTEP-based) Mac OS release.
System 1 was released on January 24, 1984. Mac OS 9 was released on October 23, 1999 (a span of 15 years 8 months and 29 days)
iPhone OS 1 was released on June 29, 2007. iOS 9 was released on September 16, 2015 (a span of 8 years 2 months and 18 days)
I wonder if the iPhone 7 will come with iOS 10, or if Apple will have merged OS X and iOS by then.