20) C
Number of passengers travelling to Spain = 34 million
Total number of passengers = 228 million
Proportion = (34 / 228) = (17 / 114) ~ (17 / 119) = (1 / 7)
Total number of passengers in 1980 (according to the graph) = 60 million
1 / 7 of 60 = 8.57 million
This is closest to C (9 million).