求美国GDP中农业部分数值和占比

1. Find data for US agricultural production and US GDP for the years 1950, 1960, 1970, 1980, 1990, and 2000.  

2. What are the current (say 2007 or later) shares of US GDP for agricultural production, the food industry, and the food and fiber sector?

以上两个数据，请大神指点，需要数据和数据来源，谢谢！

http://www.usgovernmentspending.com/us_gdp_history美国1950-2010年GDP数据
http://data.worldbank.org.cn/indicator/NV.AGR.TOTL.ZS/countries?page=6美国农业增加值占GDP比重，可根据GDP和比重计算出农业增加值。
http://www.statista.com/topics/1126/us-agriculture/美国农业总产值Gross output of U.S. farming
http://www.census.gov/compendia/statab/cats/agriculture.html美国农业详细资料

http://www.statista.com/topics/1126/us-agriculture/
http://data.worldbank.org.cn/ind ... ZS/countries?page=6 美国农业增加值比重
http://www.census.gov/compendia/statab/cats/agriculture.html

求解答