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 | Tournament | Surface | Round | Winner | Score |
| --- | --- | --- | --- | --- | --- |
| 1991 | Basel | Hard | S | John McEnroe | 6–1, 6–3 |
| 1989 | Toulouse | Hard | F | Jimmy Connors | 6–3, 6–3 |
| 1987 | Montreal / Toronto | Hard | Q | Jimmy Connors | 6–3, 3–6, 6–3 |
| 1986 | San Francisco | Carpet | F | John McEnroe | 7–6, 6–3 |
| 1985 | Montreal / Toronto | Hard | S | John McEnroe | 6–2, 6–3 |
| 1985 | Chicago | Carpet | F | John McEnroe | W/O |
| 1984 | US Open | Hard | S | John McEnroe | 6–4, 4–6, 7–5, 4–6, 6–3 |
| 1984 | Montreal / Toronto | Hard | S | John McEnroe | 2–6, 6–2, 6–3 |
| 1984 | Wimbledon | Grass | F | John McEnroe | 6–1, 6–1, 6–2 |
| 1984 | London, Queen's Club | Grass | S | John McEnroe | 6–2, 6–2 |
| 1984 | Roland Garros | Clay | S | John McEnroe | 7–5, 6–1, 6–2 |
| 1984 | Dallas WCT | Carpet | F | John McEnroe | 6–1, 6–2, 6–3 |
| 1983 | Wembley | Carpet | F | John McEnroe | 7–5, 6–1, 6–4 |
| 1983 | Cincinnati | Hard | S | John McEnroe | 6–7, 6–1, 6–4 |
| 1983 | London, Queen's Club | Grass | F | Jimmy Connors | 6–3, 6–3 |
| 1982 | San Francisco | Carpet | F | John McEnroe | 6–1, 6–3 |
| 1982 | Wimbledon | Grass | F | Jimmy Connors | 3–6, 6–3, 6–7, 7–6, 6–4 |
| 1982 | London, Queen's Club | Grass | F | Jimmy Connors | 7–5, 6–3 |
| 1982 | Philadelphia | Carpet | F | John McEnroe | 6–3, 6–3, 6–1 |
| 1981 | New York City | Carpet | RR | John McEnroe | 6–2, 7–5 |
| 1981 | Wembley | Carpet | F | Jimmy Connors | 3–6, 2–6, 6–3, 6–4, 6–2 |
| 1980 | US Open | Hard | S | John McEnroe | 6–4, 5–7, 0–6, 6–3, 7–6 |
| 1980 | Wimbledon | Grass | S | John McEnroe | 6–3, 3–6, 6–3, 6–4 |
| 1980 | Dallas WCT | Carpet | F | Jimmy Connors | 2–6, 7–6, 6–1, 6–2 |
| 1980 | Memphis | Carpet | F | John McEnroe | 7–6, 7–6 |
| 1980 | Philadelphia | Carpet | F | Jimmy Connors | 6–3, 2–6, 6–3, 3–6, 6–4 |
| 1979 | US Open | Hard | S | John McEnroe | 6–3, 6–3, 7–5 |
| 1979 | Dallas WCT | Carpet | S | John McEnroe | 6–1, 6–4, 6–4 |
| 1979 | Las Vegas | Hard | S | Jimmy Connors | 7–5, 6–4 |
| 1979 | Pepsi Grand Slam | Clay | S | Jimmy Connors | 6–3, 6–4 |
| 1978 | Masters | Carpet | RR | John McEnroe | 7–5, 3–0 RET |
| 1978 | US Open | Hard | S | Jimmy Connors | 6–2, 6–2, 7–5 |
| 1978 | Indianapolis | Clay | Q | Jimmy Connors | 3–6, 6–1, 6–1 |
| 1977 | Boston | Clay | R32 | Jimmy Connors | 5–7, 6–2, 7–5 |
| 1977 | Wimbledon | Grass | S | Jimmy Connors | 6–3, 6–3, 4–6, 6–4 |
Question:
how many were carpet courts?
Answer:
13