I didn't calculate the percentage of games that went over 6 so far, but maybe this can help you. Games played so far...
TEAM GP GF GA G/G
Atlanta 2 7 10 8,5
San Jose 2 6 11 8,5
Philadelphia 3 13 8 7,0
Pittsburgh 3 11 10 7,0
Florida 3 9 12 7,0
Nashville 3 9 12 7,0
Toronto 4 15 12 6,8
Montreal 3 7 13 6,7
Detroit 3 12 8 6,7
Tampa Bay 2 9 4 6,5
Anaheim 3 8 11 6,3
NY Rangers 4 10 15 6,3
Washington 2 7 5 6,0
Calgary 3 7 10 5,7
Carolina 4 8 14 5,5
NY Islanders 3 6 10 5,3
Buffalo 3 11 5 5,3
Vancouver 3 10 6 5,3
Phoenix 4 8 13 5,3
Minnesota 3 11 4 5,0
Los Angeles 2 7 3 5,0
St. Louis 3 7 7 4,7
Columbus 3 6 8 4,7
Boston 2 3 6 4,5
Dallas 4 13 5 4,5
New Jersey 2 5 3 4,0
Edmonton 3 5 7 4,0
Ottawa 3 5 4 3,0
Chicago 2 4 2 3,0
Colorado 2 2 3 2,5