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:
| Rk | Name | Country | Matches Played | Matches Won | Points | Prize Money (USD) |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | Stan Smith | USA | 46.0 | 41.0 | 75.0 | 154100.0 |
| 2.0 | Rod Laver | AUS | 44.0 | 37.0 | 63.0 | 78200.0 |
| 3.0 | Roy Emerson | AUS | 29.0 | 20.0 | 28.0 | 41350.0 |
| 3.0 | John Alexander | AUS | 33.0 | 22.0 | 28.0 | 31300.0 |
| 5.0 | Cliff Richey | USA | 34.0 | 23.0 | 27.0 | 24350.0 |
| 6.0 | Dick Stockton | USA | 31.0 | 20.0 | 25.0 | 23200.0 |
| 7.0 | Bob Lutz | USA | 27.0 | 17.0 | 21.0 | 41800.0 |
| 8.0 | Brian Gottfried | USA | 20.0 | 10.0 | 20.0 | 20300.0 |
| 9.0 | Colin Dibley | AUS | 23.0 | 13.0 | 18.0 | 22750.0 |
Question:
how many countries had 21 points
Answer:
1.0