Below, Corrections displays the returns over time of $1 invested in 1942 into a constant-maturity portfolio (e.g. purchase a bond of a given maturity, wait a short time, and sell it again, purchasing another bond of that given maturity with all of your proceeds (gains or losses). Data from CRSP.
The log version of the graph scales things appropriately, so that two increases mean the same thing. Note the higher slopes in the mid to late 70's due to inflation expectations.