守望黎明狂蟒查克怎么获得？

Creating "GDP in 1960" variable from GDP variables for different years

I\'m pretty new to Stata. I have a set of observation开发者_运维技巧s of the form \"CountryGDPYear\". I want to create a new variable GDP1960, which gives the GDP in 1960 of each country for each yea