Table:
text: List of AFL debuts in 2008
Change of clubs
Players who made their club debut during the 2008 season following a change of clubs
Name_ Club Debut_round Games_2008 Goals_2008 Previous_clubs
Stuart Dew Category:Articles with hCards Hawthorn 1 15 7 Port Adelaide (1997–2006)
Charlie Gardiner Category:Articles with hCards St Kilda 1 12 9 Geelong (2002–07)
Michael Gardiner Category:Articles with hCards St Kilda 1 9 1 West Coast (1997–2006)
Richard Hadley Category:Articles with hCards Carlton 1 6 2 Brisbane Lions (2001–07)
Ben Hudson Category:Articles with hCards Western Bulldogs 1 23 2 Adelaide (2004–07)
Mark Johnson Category:Articles with hCards Fremantle 1 14 8 Essendon (1999–2007)
Travis Johnstone Category:Articles with hCards Brisbane Lions 1 18 17 Melbourne (1998–2007)
Chris Judd Category:Articles with hCards Carlton 1 21 15 West Coast (2002–07)

text: List of AFL debuts in 2008
Change of clubs
Players who made their club debut during the 2008 season following a change of clubs
Name_ Club Debut_round Games_2008 Goals_2008 Previous_clubs
Steven King Category:Articles with hCards St Kilda 1 22 5 Geelong (1996–2007)
Martin Mattner Category:Articles with hCards Sydney 1 24 4 Adelaide (2002–07)
Jordan McMahon Category:Articles with hCards Richmond 1 22 6 Western Bulldogs (2001–07)
Sam Power Category:Articles with hCards North Melbourne 1 22 2 Western Bulldogs (2002–07)
Adam Schneider Category:Articles with hCards St Kilda 1 19 28 Sydney (2003–07)
Brad Symes Category:Articles with hCards Adelaide 1 16 2 Port Adelaide (2004–07)
Scott Welsh Category:Articles with hCards Western Bulldogs 1 24 43 North Melbourne (1996–99) Adelaide (2000–07)
Cameron Wood Category:Articles with hCards Collingwood 1 13 6 Brisbane Lions (2005–07)
Tim Callan Category:Articles with hCards Western Bulldogs 2 15 1 Geelong (2003–06)

Question: What is the average number of players who made their club debuts during the 2008 season after moving 21 games for a debut round less than 1 for the 2008 AFL debuts list?