From the mid-1960s, the trade balance has been in Japan's favor. According to Japanese data, its surplus with the United States grew from US$380 million in 1970 to nearly US$48 billion in 1988, declining to approximately US$38 billion in 1990. United States data on the trade relationship (which differ slightly because each nation includes transportation costs on the import side but not the export side) also show a rapid deterioration of the imbalance in the 1980s, from a Japanese surplus of US$10 billion in 1980 to one of US$60 billion in 1987, with an improvement to one of US$37.7 billion in 1990.