One Percent, from Tyler McClellan
The real return to bonds in the twentieth century was 1 percent: 1! [Source: Dimson, Marsh, Staunton]
I think a cross section of all developed countries and 100 year periodicity of returns is enough to say, things are just about right, perhaps real interest rates around the world are still slightly too high (I expect long term, 20 year tips rates to settle right below 1 percent eventually)