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 | Year | Pro Slam Championship | Surface | Opponent in the final | Score in the final |
| --- | --- | --- | --- | --- | --- |
| Runner-up | 1942.0 | US Pro | Grass | Don Budge | 2–6, 2–6, 2–6 |
| Winner | 1946.0 | US Pro | Grass | Don Budge | 6–3, 6–1, 6–1 |
| Winner | 1947.0 | US Pro | Grass | Don Budge | 3–6, 6–3, 10–8, 4–6, 6–3 |
| Runner-up | 1948.0 | US Pro | Grass | Jack Kramer | 12–14, 2–6, 6–3, 3–6 |
| Runner-up | 1949.0 | Wembley Pro | Indoor | Jack Kramer | 6–2, 4–6, 3–6, 4–6 |
| Winner | 1949.0 | US Pro | Grass | Don Budge | 9–7, 3–6, 6–3, 7–5 |
Question:
What is the average Year, when Outcome is "Winner"?
Answer:
1947.3333333333333