Final answer:
To determine the national saving rate in 1968 as a percentage of GDP, as well as the contributions from private and public savings, specific historical economic data from that year is required, which is not provided in the given information.
Step-by-step explanation:
The question asks for specific figures regarding national saving as a percentage of GDP in 1968, including the portions attributed to private saving and public saving. To answer this question accurately, we would need historical economic data from 1968 for the United States.
However, the general answer structure would be: 'In 1968, national saving was XX percent of GDP, of which YY percent was private saving and ZZ percent was public saving', where XX is the total national saving rate, YY is the private saving portion, and ZZ is the public saving portion.
According to the information provided, as of the date of the source, total U.S. national savings amount to 17% of GDP. Comparing this to the world average, the United States saves less as a percentage of its GDP since the world average is 22%.
The components of national savings include private saving, government saving, and foreign saving. However, for the specific numbers in 1968, the provided information does not offer the exact figures, making it impossible to fill in the blanks for 1968 without additional data.