400 percent.
I've observed an increased amount of interest for the 2001 Topps American Pie PAPM3 A Piece of American Pie Elvis Presley trading card, that includes a piece of a leather jacket that he wore.

A whopping four copies of that card sold during the month of June 2016 vs. only one copy during the month of April 2016, as seen in the chart below:
|
Sale Date*
|
Sold For** |
| April 24, 2016 | $46.00 |
| June 3, 2016 | $54.95-$79.99*** |
| June 28, 2016 | $45.09 |
| June 28, 2016 | $51.00 |
| June 29, 2016 | $38.00 |
Due to increased demand, the current average asking price for other copies of that card spiked to $71.86.