How many coins have a diameter of 23mm?
CREATE TABLE table_1307572_1 (reverse VARCHAR, diameter VARCHAR)
SELECT COUNT(reverse) FROM table_1307572_1 WHERE diameter = "23mm"
### Context: CREATE TABLE table_1307572_1 (reverse VARCHAR, diameter VARCHAR) ### Question: How many coins have a diameter of 23mm? ### Answer: SELECT COUNT(reverse) FROM table_1307572_1 WHERE diameter = "23mm"