Neon has three naturally occurring isotopes. In a sample of neon, 80.75% of the atoms are Ne-20, which is an isotope of neon with 10 neutrons and a mass of 19.99 AMU. Another 0.25% of the atoms are Ne-21, which is an isotope of neon with 11 neutrons and a mass of 20.99 AMU. The final 19% of the atoms are Ne-22, which is an isotope of neon with 12 neutrons and a mass of 21.99 AMU. What is the atomic mass of neon? Show your work.