Table schema:
CREATE TABLE table_name_68 (year_joined VARCHAR, school VARCHAR, size VARCHAR, ihsaa_class VARCHAR)

Question: How many years Joined have a Size smaller than 417, and an IHSAA Class of A, and a School of jac-cen-del?
SQL: SELECT COUNT(year_joined) FROM table_name_68 WHERE size < 417 AND ihsaa_class = "a" AND school = "jac-cen-del"