Life expectancy at birth is quite different from life expectancy at say 50. Back in Roman times, newborn life expectancy was about 25. But life expectancy of a

Life expectancy at birth is quite different from life expectancy at say 50. Back in Roman times, newborn life expectancy was about 25. But life expectancy of a 25 year old was beyond 50. The remaining time increased. That's not the case today anymore, especially in developed nations, but you get the idea. Your countdown ticks with less that one second per second.