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:
| Date | Tournament | Winning score | Margin of victory | Runner-up |
| --- | --- | --- | --- | --- |
| 21 May 1989 | Lancia Italian Open | −15 (71-69-68-65=273) | 1 stroke | Sam Torrance |
| 6 Aug 1989 | Scandinavian Enterprise Open | −20 (70-69-64-65=268) | 2 strokes | Michael Allen |
| 29 Oct 1989 | Volvo Masters | −6 (72-69-70-71=282) | 1 stroke | Nick Faldo |
| 5 Aug 1990 | PLM Open | −18 (64-67-70-69=270) | 4 strokes | Vijay Singh |
| 2 Sep 1990 | Ebel European Masters Swiss Open | −21 (70-65-66-66=267) | 2 strokes | John Bland |
| 22 Mar 1992 | Portuguese Open | −15 (67-71-67-68=273) | 1 stroke | Anders Forsbrand |
| 15 Aug 1993 | Hohe Brucke Austrian Open | −14 (65-69-72-68=274) | Playoff | Anders Sørensen |
Question:
Which Date has a Winning score of −15 (71-69-68-65=273)?
Answer:
21 May 1989