user: Question: Name the total number of years for quarterfinals
Columns: ['Year', 'Record', 'Regular Season Finish', 'Playoffs', 'Avg Attend.']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1975.0, '16–6', '1st, Eastern Division', 'NASL Champions', 10728.0]
SQL:

assistant: SELECT COUNT("Year") FROM "Table" WHERE "Playoffs" = 'quarterfinals';