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:
| Issue Date | Album | Artist |
| --- | --- | --- |
| January 7 | Thriller | Michael Jackson |
| January 14 | Thriller | Michael Jackson |
| January 21 | Thriller | Michael Jackson |
| January 28 | Thriller | Michael Jackson |
| February 4 | Thriller | Michael Jackson |
| February 11 | Thriller | Michael Jackson |
| February 18 | Thriller | Michael Jackson |
| February 25 | Thriller | Michael Jackson |
| March 3 | Thriller | Michael Jackson |
| March 10 | Thriller | Michael Jackson |
| March 17 | Thriller | Michael Jackson |
| March 24 | Thriller | Michael Jackson |
| March 31 | Thriller | Michael Jackson |
| April 7 | Thriller | Michael Jackson |
| April 14 | Thriller | Michael Jackson |
| April 21 | Footloose | Soundtrack |
| April 28 | Footloose | Soundtrack |
| May 5 | Footloose | Soundtrack |
| May 12 | Footloose | Soundtrack |
| May 19 | Footloose | Soundtrack |
| May 26 | Footloose | Soundtrack |
| June 2 | Footloose | Soundtrack |
| June 9 | Footloose | Soundtrack |
| June 16 | Footloose | Soundtrack |
| June 23 | Footloose | Soundtrack |
| June 30 | Sports | Huey Lewis and the News |
| July 7 | Born in the U.S.A. | Bruce Springsteen |
| July 14 | Born in the U.S.A. | Bruce Springsteen |
| July 21 | Born in the U.S.A. | Bruce Springsteen |
| July 28 | Born in the U.S.A. | Bruce Springsteen |
| August 4 | Purple Rain | Prince and the Revolution / Soundtrack |
| August 11 | Purple Rain | Prince and the Revolution / Soundtrack |
| August 18 | Purple Rain | Prince and the Revolution / Soundtrack |
| August 25 | Purple Rain | Prince and the Revolution / Soundtrack |
| September 1 | Purple Rain | Prince and the Revolution / Soundtrack |
| September 8 | Purple Rain | Prince and the Revolution / Soundtrack |
| September 15 | Purple Rain | Prince and the Revolution / Soundtrack |
| September 22 | Purple Rain | Prince and the Revolution / Soundtrack |
| September 29 | Purple Rain | Prince and the Revolution / Soundtrack |
| October 6 | Purple Rain | Prince and the Revolution / Soundtrack |
| October 13 | Purple Rain | Prince and the Revolution / Soundtrack |
| October 20 | Purple Rain | Prince and the Revolution / Soundtrack |
| October 27 | Purple Rain | Prince and the Revolution / Soundtrack |
| November 3 | Purple Rain | Prince and the Revolution / Soundtrack |
| November 10 | Purple Rain | Prince and the Revolution / Soundtrack |
| November 17 | Purple Rain | Prince and the Revolution / Soundtrack |
| November 24 | Purple Rain | Prince and the Revolution / Soundtrack |
| December 1 | Purple Rain | Prince and the Revolution / Soundtrack |
| December 8 | Purple Rain | Prince and the Revolution / Soundtrack |
| December 15 | Purple Rain | Prince and the Revolution / Soundtrack |
| December 22 | Purple Rain | Prince and the Revolution / Soundtrack |
| December 29 | Purple Rain | Prince and the Revolution / Soundtrack |
Question:
how long did michael jackson hold the top spot?
Answer:
15 weeks