Table:
text: 2006–07 Taça de Portugal
Format and schedule
Format and schedule
Round Dates Clubs_from_the_previous_round Clubs_involved Fixtures
First round 3 September 2006 none 127 60
Second round 24 September 2006 60 winners from the first round 122 56
Third round 11–12 November 2006 56 winners from the second round 81 40
Fourth round 21 December 2006 6–7 January 2007 40 winners from third round 57 28
Fifth round 21 January 2007 28 winners from fourth round 27 13
Sixth round 10 February 2007 13 winners from fifth round 15 7
Quarter-finals 28 February 2006 25 March 2007 7 winners from sixth round 8 4
Semi-finals 18–19 April 2007 4 winners from the quarterfinals 4 2
Final 27 May 2007 2 winners from the semifinals 2 1

Question: If 4 clubs are involved, what is the average number of games at the 2006-07 Taça de Portugal?

Question: What is the total of matches in the sixth round of the 2006/07 Taça de Portugal when more than 15 clubs were involved?