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 | Venue | Opponent | Score | Result | Competition |
| --- | --- | --- | --- | --- | --- | --- |
| 1. | 29 March 2000 | Vasil Levski National Stadium, Sofia | Belarus | 1–0 | 4–1 | Friendly |
| 2. | 7 October 2000 | Georgi Asparuhov Stadium, Sofia | Malta | 3–0 | 3–0 | 2002 World Cup qualifier |
| 3. | 27 March 2003 | Stadion Mladost, Kruševac | Serbia and Montenegro | 2–1 | 2–1 | Friendly |
| 4. | 7 June 2003 | Vasil Levski National Stadium, Sofia | Belgium | 2–2 | 2–2 | Euro 2004 qualifier |
| 5. | 12 November 2005 | Vasil Levski National Stadium, Sofia | Georgia | 5–0 | 6–2 | Friendly |
| 6. | 12 November 2005 | Vasil Levski National Stadium, Sofia | Georgia | 6–2 | 6–2 | Friendly |
| 7. | 9 May 2006 | Nagai Stadium, Osaka | Japan | 1–0 | 2–1 | 2006 Kirin Cup |
Question:
what is their most frequent competition?
Answer:
Friendly