CREATE TABLE table_66597 ("Rank" FLOAT, "City" TEXT, "Population" FLOAT, "Year of Census or Estimate" FLOAT, "Country" TEXT)

In what Year of Census or Estimate is the Toronto Population larger than 1,556,396?
SELECT SUM("Year of Census or Estimate") FROM table_66597 WHERE "Population" > '1,556,396' AND "City" = 'toronto'
SELECT SUM("Year of Census or Estimate") FROM "table_66597" WHERE "City" = 'toronto' AND "Population" > '1,556,396'