The given line graph illustrates how much carbon dioxide (CO2) emissions were produced by people in four countries from 1967 to 2007. In general, the total amount of pollution in this time fluctuated in limits between 1 and 11 tons, where the United Kingdom was a leader, meanwhile the lowest rates belonged to Portugal during almost the whole period. From 1967 all items except the UK increased their emissions substantively. Sweden's figure reached their own peak of just over 10 tonnes in about 1977 and then declined sharply to the lowest point of approximately 2 tons in 2007. Whereas, the indicators of Portugal and Italy started their significant rise from the lowest level of just under 2 and 4 tons to their peak of 5 and 8 tons respectively in 2007. As for the United Kingdom, although a moderate decrease is observed throughout the entire period by almost 2 tons, the highest position still belonged to them in comparison to other considered countries.