Grade

Division

Standard

1

0 < R ≤ 0.2

More worse than normal

2

0.2 < R ≤ 0.8

Slightly worse than normal

3

0.8 < R ≤ 1.2

Equal to normal years

4

1.2 < R ≤ 1.8

Slightly better than normal

5

R > 1.8

More better than normal