user: Question: How many years was the issue price $19.95?
Columns: ['Year of issue', 'Theme', 'Composition', 'Issue price', 'Mintage']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1997.0, 'Hockey Hall of Fame Inductees Medallion Collection', 'Sterling Silver', '$69.99', '1,997']
SQL:

assistant: SELECT COUNT("Year of issue") FROM "Table" WHERE "Issue price" = '$19.95';