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:
| Year | Location | Gold | Silver | Bronze |
| --- | --- | --- | --- | --- |
| 1958 | Tokyo | Sachika Kamo | Desideria Ampon | Liu Shang-Ku |
| 1962 | Jakarta | Akiko Fukui | Reiko Miyagi | Desideria Ampon\n Patricia Yngayo |
| 1966 | Bangkok | Lany Kaligis | Kazuko Kuromatsu | Lita Liem Sugiarto\n Phanow Sudsawasdi |
| 1974 | Tehran | Lita Liem Sugiarto | Paulina Pesahov | Lany Kaligis |
| 1978 | Bangkok | Lee Duk-Hee | Chen Chuan | Kiyoko Nomura\n Sonoe Yonezawa |
| 1982 | New Delhi | Etsuko Inoue | Kim Soo-Ok | Yu Liqiao |
| 1986 | Seoul | Li Xinyi | Lee Jeong-Soon | Kim Soo-Ok |
| 1990 | Beijing | Akiko Kijimuta | Chen Li | Park Mal-Sim\n Kim Il-Soon |
| 1994 | Hiroshima | Kimiko Date | Naoko Sawamatsu | Yayuk Basuki\n Chen Li |
| 1998 | Bangkok | Yayuk Basuki | Tamarine Tanasugarn | Li Fang\n Yi Jingqian |
| 2002 | Busan | Iroda Tulyaganova | Tamarine Tanasugarn | Shinobu Asagoe\n Cho Yoon-Jeong |
| 2006 | Doha | Zheng Jie | Sania Mirza | Li Na\n Aiko Nakamura |
| 2010 | Guangzhou | Peng Shuai | Akgul Amanmuradova | Kimiko Date-Krumm\n Sania Mirza |
Question:
how long has it been since japan won gold?
Answer:
20 years