Table:
text: List of locomotives in China
Diesel-electric transmission
Imported
Model Build_year Top_speed_In_operation_km_h_ Power_output_kW_ Total_production
6Y2 1958—1961 101 4740 25
6G1 1971 120 5100 2
6G 1973 112 5400 40
6K 1986–1987 100 5100 85
8G 1987–1990 100 2×3200 100
8K 1987 100 2×3200 150

Question: Tell me the year of manufacture for the total production 150 in list Locomotives in imported diesel-electric transmissions in China. ?