Variables

Air transportation

Passenger traffic (10 000 persons): x1

Freight traffic (10 000 tons): x2

Local economy

Gross domestic product of Tianjin (100 million yuan): y1

Total value of imports & exports in foreign trade (USD 100 million): y2

Total government revenue (100 million yuan): y3

Number of employment personnel (10,000 persons): y4

Foreign exchange earning from international tourists (USD 10,000): y5

Gross product of transportation storage and post services(100 million yuan):y6

Gross product of wholesale and retail trade (100 million yuan): y7

Per capita annual disposable income of urban households (yuan): y8

Foreign capital actually used (USD 10 000): y9