16.6% of the tokens were sold. So 48.4% of the token supply will be burned.
what happens to the other 35%?

According to their whitepaper, 17% of tokens are reserved for the social network development, 8% for the bounty, 9% for the company and 1% for the team and advisory staff.
65% of available tokens were out for sale, 16.6% were sold, 65 - 16.6 = 48.4%.
...it was sphere's job to explain but they don;t do..once again sphere have no skill in comunication with people