user: Question: on 19 April 1985 how many of number last flew
Columns: ['Number', 'Registration', 'First flew', 'Last flew', 'Flying hours', 'Location']
Types: ['real', 'text', 'text', 'text', 'real', 'text']
Sample row: [1.0, 'F-WTSS', '2 March 1969', '19 October 1973', 812.0, 'The Museum of Air and Space , Le Bourget, France']
SQL:

assistant: SELECT COUNT("Number") FROM "Table" WHERE "Last flew" = '19 April 1985';