I am amazed that Atlas rockets are still in use. I know the Atlas V is relatively new (20 years old) but the earliest Atlas rockets date back to the year I was born.
Delta was originally derived from the PGM-17 Thor Intermediate Ballistic Missile which became operation in late 1957 and which was derived to become the Thor-Able rocket used between 1958 and 1960. In fact, the first Delta rocket was called the Thor-Delta, before the Thor was dropped.
The first Atlas missiles also launched in 1957.
Interestingly, both Atlas and Delta are in their final launches, to be replaced by the Vulcan rocket this decade.
And don’t forget the Titan family which lasted from 1959 to 2005.