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:
| Outcome | No. | Date | Championship | Surface | Opponent | Score |
| --- | --- | --- | --- | --- | --- | --- |
| Runner-up | 1. | 1973 | Baltimore, U.S. | Hard (i) | Jimmy Connors | 4–6, 5–7 |
| Winner | 1. | 1974 | Baltimore, U.S. | Carpet | Clark Graebner | 6–2, 6–1 |
| Runner-up | 2. | 1974 | Birmingham, U.S. | Carpet | Jimmy Connors | 5–7, 3–6 |
| Winner | 2. | 1974 | Paramus, U.S. | Indoor | Jürgen Fassbender | 6–1, 6–3 |
| Winner | 3. | 1974 | Jackson, U.S. | Carpet | Karl Meiler | 7–6, 7–5 |
| Runner-up | 3. | 1975 | Maui, U.S. | Hard | Jimmy Connors | 1–6, 0–6 |
| Runner-up | 4. | 1975 | Hong Kong | Hard | Tom Gorman | 3–6, 1–6, 1–6 |
| Winner | 4. | 1977 | Little Rock, U.S. | Carpet | Haroon Rahim | 6–2, 6–4 |
| Runner-up | 5. | 1977 | San Jose, U.S. | Hard | Jiří Hřebec | 6–3, 4–6, 5–7 |
| Winner | 5. | 1977 | Hampton, U.S. | Carpet | Stan Smith | 4–6, 6–3, 6–2, 1–6, 6–3 |
| Winner | 6. | 1977 | Stockholm, Sweden | Hard (i) | Raymond Moore | 6–2, 6–4 |
| Winner | 7. | 1978 | St. Louis WCT, U.S. | Carpet | Eddie Dibbs | 7–6, 6–4 |
| Runner-up | 6. | 1980 | Surbiton, England | Grass | Brian Gottfried | 3–6, 3–6 |
| Runner-up | 7. | 1981 | Los Angeles, U.S. | Hard | John McEnroe | 7–6, 3–6, 3–6 |
| Runner-up | 8. | 1981 | Cologne, Germany | Hard (i) | Ivan Lendl | 3–6, 3–6 |
| Runner-up | 9. | 1981 | Stockholm, Sweden | Hard (i) | Gene Mayer | 4–6, 2–6 |
| Winner | 8. | 1981 | Bologna, Italy | Carpet | Ilie Năstase | 7–5, 6–3 |
| Runner-up | 10. | 1982 | Stuttgart Outdoor, Germany | Clay | Ramesh Krishnan | 7–5, 3–6, 3–6, 6–7 |
| Winner | 9. | 1982 | Cleveland, U.S. | Hard | Robert Van't Hof | 7–5, 6–3 |
| Winner | 10. | 1983 | Gstaad, Switzerland | Clay | Tomáš Šmíd | 6–0, 6–3, 6–2 |
Question:
what surface was used before carpet?
Answer:
Hard (i)