I use the geometric mean to calculate my average annual growth rate. For a 11 year period, my average annual growth rate is 9.12%
it is more appropriate to use the geometric mean rather than the arithmetic mean. The geometric mean takes into account the compounding effect of growth over time...
Since I have quite a bit of money in my savings account that pays only 0.01% in interest, buying I-Bonds at 9.62% is a no-brainer. Earlier this month, I set up my account through TreasuryDirect with my wife as co-owner and set up her account with me as a co-owner. $10000 went into each account.