Year | Correlation degree | |||
r1 | r2 | r3 | Quality level | |
2011 | 0.528 | 0.650 | 0.815 | Ⅲ level |
2012 | 0.433 | 0.502 | 0.347 | Ⅲ level |
2013 | 0.529 | 0.810 | 0.538 | Ⅱ level |
2014 | 0.137 | 0.623 | 0.090 | Ⅱ level |
2015 | 0.422 | 0.846 | 0.457 | Ⅱ level |
2016 | 0.467 | 0.816 | 0.439 | Ⅱ level |