When someone says that the flow is 16 years in an attempt to project that 16 years is what it would be for someone hired today, it shows an extreme lack of common sense. Same for upgrade and same for reserve.
To answer your question, current upgrade is about 8 years, reserve probably about 2-3 (don't quote, just an educated guess) and flow 16. If you want to use these numbers to project a new-hires career expectations, then be my guest
