CREATE TABLE table_26650 ("State  ( class ) " CLOB, "Vacator" CLOB, "Reason for change" CLOB, "Successor" CLOB, "Date of successors formal installation" CLOB)

List the number of vacators when successors were formally installed on June 22, 1868.
SELECT COUNT("Vacator") FROM table_26650 WHERE "Date of successors formal installation" = 'June 22, 1868'
SELECT COUNT("Vacator") FROM "table_26650" WHERE "Date of successors formal installation" = 'June 22, 1868'