user: Question: What was the average mintage for that of artist Celia Godkin, before the year 2010?
Columns: ['Year', 'Artist', 'Composition', 'Mintage', 'Issue Price']
Types: ['real', 'text', 'text', 'real', 'text']
Sample row: [1998.0, 'Pierre Leduc', '99.999% pure gold', 1998.0, '$999.99']
SQL:

assistant: SELECT AVG("Mintage") FROM "Table" WHERE "Artist" = 'Celia Godkin' AND "Year" < 2010.0;