potassium	variety
1	27.9	1
2	27	1
3	26	1
4	26.5	1
5	27	1
6	27.5	1
7	24.2	2
8	24.7	2
9	25.6	2
10	26	2
11	27.4	2
12	26.1	2
13	29.1	3
14	27.7	3
15	29.9	3
16	30.7	3
17	28.8	3
18	31.1	3