CREATE TABLE "table1_2417340_3" (
  "state_class" text,
  "vacator" text,
  "reason_for_change" text,
  "successor" text,
  "date_of_successors_formal_installation" text
);

Question: List the number of vacators when successors were formally installed on June 22, 1868.
SQL: SELECT COUNT("vacator") FROM "table1_2417340_3" WHERE "date_of_successors_formal_installation"='June 22, 1868';

Question: List all state classes when successors were formally installed on June 22, 1868.
SQL: SELECT "state_class" FROM "table1_2417340_3" WHERE "date_of_successors_formal_installation"='June 22, 1868';