A certain element X has four isotopes.

· 95.0% of X has a mass of 31.97207 amu. · 0.760% of X has a mass of 32.97146 amu. · 4.22% of X has a mass of 33.96786 amu. · 0.0140% of X has a mass of 35.96709 amu.

What is the average atomic mass of element X?