CREATE TABLE table_31610 ("Year of election" FLOAT, "Candidates elected" FLOAT, "# of seats available" FLOAT, "# of votes" TEXT, "% of popular vote" TEXT)

What is the percentage of the popular vote when there were 90 seats available?
SELECT "% of popular vote" FROM table_31610 WHERE "# of seats available" = '90'
SELECT "% of popular vote" FROM "table_31610" WHERE "# of seats available" = '90'