Technology/What Was the Most Important Invention?

Technology has increased the quality of life for many people, although, unfortunately, there are still places in the world where people suffer because of the lack of technology.

There are five inventions set forth below, listed in random order. Which of these was the most important to humankind, the next most important, etc. The most Important should be set forth as 1, the next most important as 2, etc.

Electricity

Telephone

Airplane

Polio Vaccine

Computer