Write SQL query to solve given problem: What is the percentage of Harvard university's international students in 2011?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T1.pct_international_students FROM university_year AS T1 INNER JOIN university AS T2 ON T1.university_id = T2.id WHERE T1.year = 2011 AND T2.university_name = 'Harvard University'