Question: What is the height of the Fort Peck Dam which was built before 1968, is locaTEd in the United States and has a dam type of TE ?
SQL: SELECT "Structure Height [m]" FROM "2-12755231-1" WHERE "Year" < 1968.0 AND "Type" = 'TE' AND "Country" = 'United States' AND "Name" = 'Fort Peck Dam';