Life expectancy varies widely depending on many factors. For those in the western world one big variable is when you were born.
In the US if you were born in 1960 it's 70-75 years. Born in 2000 it rises to 75-80 years.
http://ucatlas.ucsc.edu/life/index.html
Obviously if you smoke and do other unhealthy crap you're going to pull the numbers down. Ot maybe you just get unlucky and get killed young or get some fatal disease.
Now, if you take out all those people who die from something other than age you end up with a different number for sure.
In my case, mom and dad are late 60's and very active and always have been. Grandma is 93 and just stopped driving 2 years ago. MIL is 87 and just stopped working fulltime last year. Non of them have ever smoked or drank. FIL died in a fire at 44 because he was passed out drunk. Average age of death for those 5 if the 4 living died tomorrow is 72.
The truth is, if your not unlucky and get killed or get the wrong DNA and you take reasonabily good care of yourself you're likely to live until at least 80 if not 90. Especially with the advancements in medicene. And while you might not run a 4 minute mile, you'll be able to be a lot more active than seniors of a few decades ago who didn't exercise ever, smoked like chimney's, and didn't have mri's and such to catch things early.
Bottomline: you better have a lot money or you're going to regret it. In fact, you might well die early just due to boredom and lack of activity if you can't afford to do things.