Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year | Winner | Country | Score | To par | 1st prize ( $ ) |
| --- | --- | --- | --- | --- | --- |
| 1972.0 | David Graham | Australia | 278.0 | −6 | 30000.0 |
| 1971.0 | Bobby Mitchell | United States | 262.0 | −22 | 30000.0 |
| 1970.0 | Bruce Devlin | Australia | 268.0 | −12 | 30000.0 |
| 1969.0 | Charles Coody | United States | 271.0 | −9 | 22000.0 |
| 1968.0 | Dave Stockton | United States | 276.0 | −8 | 22000.0 |
| 1967.0 | Gardner Dickinson | United States | 271.0 | −9 | 20700.0 |
| 1966.0 | R. H. Sikes | United States | 268.0 | −16 | 20000.0 |
| 1965.0 | Dan Sikes | United States | 272.0 | −12 | 25000.0 |
| 1964.0 | Tony Lema | United States | 270.0 | −14 | 20000.0 |
| 1963.0 | Arnold Palmer | United States | 273.0 | −11 | 22000.0 |
Question:
What is the total number of 1st prize ($) that has a United States country with a score lower than 271 and in a year after 1964 with a winner of Bobby Mitchell?
Answer:
1.0