1968
 JanFebMarAprMayJunJulAugSepOctNovDec
1 1 --- --- 1 --- 1 1,2 --- 1 1 1 1
2 --- 1 1 1 --- 1 1 --- 1 --- --- ---
3 --- 1 1 1 --- 1 --- --- 1 1 1 1
4 1 1 --- --- --- --- --- --- --- 1 --- ---
5 --- --- 1 --- 1 --- --- --- --- 1 --- 1
6 1 1 --- 1 1 --- --- --- --- 1 1 ---
7 --- --- 1 1 1 1,2 --- --- 1 1 1 ---
8 1 --- 1 --- 1 --- 1,2 --- --- --- 1 1
9 1 --- 1 1 --- --- 1 --- --- 1 --- ---
10 1 1 --- 1,2 1,2 --- --- --- 1,2 --- --- ---
11 1 1 1,2 1 --- --- --- --- --- 1,2 --- ---
12 1 1 1 --- --- 1,2 --- --- 1,2 1 --- 1
13 --- 1 --- --- --- 1 --- --- --- 1 1 1
14 --- 1 1 1 --- 1 1 --- 1 1 1 1
15 --- --- --- 1 --- --- --- --- 1 --- 1 ---
16 1 1 1 --- --- --- 1 --- 1 1 1 1
17 1 1 1 1 --- --- --- --- 1 1,2 1 1
18 --- --- --- 1,2 1 --- 1 --- 1 --- --- 1
19 --- --- 1 1 --- --- 1 --- --- 1 --- 1
20 --- 1 --- 1 --- 1 1,2 --- 1 1 1 ---
21 --- 1 1 --- --- 1,2 1 --- --- --- 1 1
22 --- 1 --- 1 1 1 1 --- --- 1,2 1 1
23 --- 1 1 --- 1,2 1 --- --- 1,2 --- --- 1
24 --- 1,2 1,2 --- 1 --- --- --- --- 1 1 1
25 --- 1 --- 1 --- 1 --- --- 1,2 --- --- ---
26 1 --- 1 1 1,2 --- --- --- --- --- --- 1
27 1 1 --- 1 --- --- --- --- 1 1,2 --- 1
28 --- --- 1 1 1 --- --- --- 1 1 1 1
29 1 --- --- 1 --- --- --- --- 1 1 --- 1
30 1   1 --- --- --- --- --- 1 --- 1 1
31 1   1   1   --- ---   1,2   1