I'm sure that in biblical times, 70 was not uncommon... so those who made it were considered 'normal'. They knew that war and accidents etc. happened.
By the Dark Ages and into Medieval eras, more wars and disease etc. were affecting 'average' life span..including, eventually, The Black Death. Since modern medicine in the 1800s to the present, 'average' has gradually increased.
I am the result of thousands of lucky circumstances that didn't kill my ancestors... so are all of you.
   Actually, 2 of my ancestors died at sea in the mid 1600s... but they had a son in England who didn't emigrate to the colonies until several years later.

Every set of statistics has to be understood in context....