How many Apollo astronauts are still alive? [Further Updated: 22/04/2019]

[I have updated this article again after previously re-releasing it when news of the death of Apollo 12 and Skylab 2 commander, Al Bean became widely known, although it had been announced a few days previously. With the death of Al Bean, just four Moon-walkers survive, the youngest of them, 83 years old. Al Bean [...]