user: Question: How many vocal parts are there when the year of songs original release date as listed in rock band 3 was 2000?
Columns: ['Song title', 'Artist', 'Year Year of songs original release, as listed in Rock Band 3', 'Genre', 'Keyboard support', 'Vocal parts', 'Nintendo DS setlist']
Types: ['text', 'text', 'real', 'text', 'text', 'real', 'text']
Sample row: ['" 20th Century Boy "', 'T. Rex', 1973.0, 'Glam Rock', 'Yes', 3.0, 'No']
SQL:

assistant: SELECT SUM("Vocal parts") FROM "Table" WHERE "Year Year of songs original release, as listed in Rock Band 3" = 2000.0;