What is the percentage of the international students in University of Oslo in 2015?
percentage of the international students refers to pct_international_students; in 2015 refers to year = 2015; in University of Oslo refers to university_name = 'University of Oslo';
SELECT T2.pct_international_students FROM university AS T1 INNER JOIN university_year AS T2 ON T1.id = T2.university_id WHERE T1.university_name = 'University of Oslo' AND T2.year = 2015
database name:db_id university
country table country Cols: id dtype integer, country name dtype text, 
ranking_system table ranking_system Cols: id dtype integer, system name dtype text, 
ranking_criteria table ranking_criteria Cols: id dtype integer, ranking system id dtype integer, criteria name dtype text, 
university table university Cols: id dtype integer, country id dtype integer, university name dtype text, 
university_ranking_year table university_ranking_year Cols: university id dtype integer, ranking criteria id dtype integer, year dtype integer, score dtype integer, 
university_year table university_year Cols: university id dtype integer, year dtype integer, number of students dtype integer, student staff ratio dtype real, pct internation student dtype integer, pct female students dtype integer, 
