Historical returns. Calculate the arithmetic average return of U.S. Treasury bills, long-term government bonds, and large-company stocks for 1950 to 1959, 1960 to 1969, 1970 to 1979, and 1980 to 1989. Which had the highest return? Which had the lowest return? Click on "Get more help" menu, then select "Spreadsheet" to see Table 8.1-Year-by-Year Returns, 1950-1999. What is the average return of U.S. Treasury bills for 1950 to 1959, 1960 to 1969, 1970 to 1979, and 1980 to 1989? The average return of U.S. Treasury bills from 1950 to 1959 is %. (Round to two decimal places.)