I know that there is no guarantee, it is unpredictable, etc. However, in order to calculate my possible retirement date as close as possible, I need to assume some interest rate. I would like to have approx 60% invested in some index stocks fund and 40% in some index bond fund, possibly with Vanguard. I do not plan to actively manage my investments, no ETFs, just 60/40 as described above. I might be willing to go 70/30. I need to assume that I will have to pay taxes on the earned interest. I actually do not know exactly my tax rate, maybe 20%? Is 7% (after tax) rate reasonable to assume, or is it more like 5%? Thanks!