question: Since the 90 's , how has Portugal 's economic development model been changing ?
answer: changing to a system that is focused on exports , private investment and the development of the high-tech sector
turker_answer: Portugal 's economic development model has been changing to a system that is focused on exports , private investment and the development of the high-tech sector since the 90 's .
rule-based: Since the 90 's , Portugal 's economic development model has been changing by changing to a system that is focused on exports , private investment and the development of the high-tech sector .