Robert Freitas analyzed the statistically the challenge of life extension. Part of his analysis is shown in the table above
The longest life expectancies is about 86 years for Japanese women. This is almost as good as a 10% reduction in medically preventable conditions versus an 80 year life expectancy, which would result in 88 year life expectancies.
The Scientific Conquest of death is a 296 page collection of essays from Aubrey de Grey, Robert Freitas and others.
There are many causes of death, so it would take a lot of new technology to eliminate or mitigate each one or each category.
Simple existing technologies that are properly applied can greatly reduce deaths worldwide.
Nextbigfuture has looked at improvements to agriculture
There are cheap ways to prevent or cure disease
Conditions can be improved to reduce deaths. Air pollution can be reduced and water quality can be improved.