Table 1 Estimated Total Returns
State of the Economy	Probability	T-Bond	SETX	Golden	S&P 500
Recession	5%	5%	-19%	20%	-14%
Below Average	15%	5%	2%	13%	3%
Average	45%	5%	9%	10%	11%
Above Average	25%	5%	34%	5%	22%
Boom	10%	5%	25%	-5%	33%

Why is the T-bond return in table 1 shown to be independent of the state of the economy? Is the return on a 1-year T-bond risk-free?