The supply of STEEM grows exponential instead of linear. For example:

• 9.5% of a supply of 250,000,000 is 23,750,000 new STEEM per year.
• 10 years later: 5% of a STEEM supply of 479,000,000 is 23,949,932.76 new STEEM per year.

Besides, the price of STEEM will be much higher 10 years from now :)