data={{1980,338.7},{1982,341.2},{1984,344.4},{1986,347.2},{1988,351.5},{1990,354.2},{1992,356.3},{1994,358.6},{1996,362.4},{1998,366.5},{2000,369.4},{2002,373.2},{2004,377.5},{2006,381.9},{2008,385.6},{2010,389.9},{2012,393.8}};

Export["CO2.tsv",data,"TSV"]