Below are the returns of the long-term US government bonds. Calculate the average and the standard deviation of returns.
Year Return
1990 7.13%
1991 18.39%
1992 7.79%
1993 15.48%
1994 –7.18%
1995 31.67%
1996 –0.81%
1997 15.08%
1998 13.52%
1999 –8.74%