This chart from the CDC shows the annual age adjusted death rate.
The CDC comments that
"The risk of dying decreased for all age groups but was greater for younger age groups with a 94 percent reduction in death rates at 1–4 years compared with a 38 percent decline at 85 years or more."
So put another way the improvement was much greater for young people than the extremely old.
Another CDC comment said that
"Heart disease, cancer, and stroke were among the five leading causes every year between 1935 and 2010."
That gives the impression that not a lot of progress is being made in treating these three causes of death.