rownames,mass,year
1,2.259,2004
2,2.247,2004
3,2.254,1987
4,2.298,1988
5,2.287,1971
6,2.254,2007
7,2.268,2007
8,2.214,1974
9,2.268,2007
10,2.274,2004
11,2.271,1997
12,2.268,1994
13,2.298,1974
14,2.292,1996
15,2.274,1999
16,2.234,1993
17,2.238,1998
18,2.252,2000
19,2.249,2007
20,2.234,2001
21,2.275,1994
22,2.23,1972
23,2.236,1992
24,2.233,1970
25,2.255,2001
26,2.277,2001
27,2.256,2004
28,2.282,2001
29,2.235,2001
30,2.235,2002