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 | Name | Birth Date | Winner | Awarding Age |  |
| --- | --- | --- | --- | --- | --- |
| 1998 | Nick Cheung | 1967-12-02 | Winner | 30 years, 352 days |  |
| 1998 | Chin Kar Lok | 1965-08-06 | Winner | 33 years, 105 days |  |
| 2002 | Moses Chan | 1971-04-16 | Winner | 31 years, 217 days |  |
| 2003 | Raymond Lam | 1979-12-08 | Winner | 23 years, 346 days | Youngest winner |
| 2004 | Ron Ng | 1979-09-02 | Winner | 25 years, 78 days |  |
| 2005 | Bosco Wong | 1980-12-13 | Winner | 24 years, 341 days |  |
| 2006 | Kenneth Ma | 1974-02-13 | Winner | 32 years, 270 days |  |
| 2007 | Amigo Choi | 1979-05-08 | Winner | 28 years, 193 days |  |
| 2008 | Wong Cho Lam | 1980-01-09 | Winner | 28 years, 311 days |  |
| 2009 | Ngo Ka-nin | 1976-09-26 | Winner | 33 years, 69 days |  |
| 2010 | Raymond Wong | 1976-08-25 | Winner | 34 years, 102 days | Oldest winner |
| 2011 | Jin Au-Yeung | 1982-06-04 | Winner | 29 years, 184 days |  |
| 2012 | Oscar Leung | 1979-03-26 | Winner | 33 years, 266 days |  |
Question:
how many winners have been at least 30 years old?
Answer:
7