In 1959, the ratio of added value of Tibet's primary, secondary and tertiary industries was 1:0.17:0.19; primary industry being the largest industry proves that Tibet was a typical agricultural society. In 1984, the ratio of added value of the three types of industries was 1:0.44:0.71; the plunging ratio of the added value of primary industry in the GDP indicates that it was beginning to lose its domination in the region's economy. In 1997, the same ratio turned out to be 1:0.58:1.07; the added value of primary industry historically gave way to that of tertiary industry. In 2003, the ratio became 1:1.17:2.38; the added value of tertiary industry made up more than half of the region's GDP, and the added value of agriculture took the last place. Tibet's industrial structure was upgraded again, forming a pattern with tertiary industry as the largest, secondary industry taking the middle place and primary industry as the smallest one in light of their weight in the region's GDP. This pattern has since continued, indicating the soundness of regional economic development.