what are japan's major exports?
['Vehicles: US$148.8 billion (21.1% of total exports)', 'Machinery including computers: $137 billion (19.4%)', 'Electrical machinery, equipment: $103.1 billion (14.6%)', 'Optical, technical, medical apparatus: $39.1 billion (5.5%)', 'Iron, steel: $26.1 billion (3.7%)', 'Plastics, plastic articles: $25.2 billion (3.6%)']