However, the world is healther now than it has ever been. The rate of increase in life expectancy after 1950 is over 80,000 times great than before 1950. There has never been a year since 1950 where life expectancy has decreased. For every week since 1950, life expectancy has increased 2 days. We are definitely healthier now then we have ever been. The reason for the 25 year increase in life expectancy is almost exclusively due to prevention, not clinical medicine. Clinical medicine is important, but of the 25 years increase, 22 has been due to prevention.