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 of election | Candidates elected | # of seats available | # of votes | % of popular vote |
| --- | --- | --- | --- | --- |
| 1963 | 7 | 108 | n.a. | 15.5% |
| 1967 | 20 | 117 | n.a. | 25.9% |
| 1971 | 19 | 117 | n.a. | 27.1% |
| 1975 | 38 | 125 | n.a. | 28.9% |
| 1977 | 33 | 125 | n.a. | 28.0% |
| 1981 | 21 | 125 | n.a. | 21.2% |
| 1985 | 25 | 125 | 865,507 | 23.8% |
| 1987 | 19 | 130 | 970,813 | 25.7% |
| 1990 | 74 | 130 | 1,509,506 | 37.6% |
| 1995 | 17 | 129 | 854,163 | 20.6% |
| 1999 | 9 | 103 | 551,009 | 12.6% |
| 2003 | 7 | 103 | 660,730 | 14.7% |
| 2007 | 10 | 107 | 741,043 | 16.8% |
| 2011 | 17 | 107 | 980,204 | 22.73% |
Question:
how many more seats were available in 1975 than 1963?
Answer:
17