user: Question: How many years was best musical revival nominated?
Columns: ['Year', 'Award', 'Category', 'Nominee', 'Result']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [2009.0, 'Laurence Olivier Award', 'Best Musical Revival', 'Best Musical Revival', 'Won']
SQL:

assistant: SELECT COUNT("Year") FROM "Table" WHERE "Nominee" = 'best musical revival';