Hi my original dataset (year 2007) had over 2000 variables and i dropped them all except from 8 variables which i kept. I did the same thing with the datasets for different years (2008, 2009, 2010, 2011 and 2012) so each dataset had the same 8 variables. Using the APPEND in stata i appended these datasets together to make one overall dataset to then carry out a cross sectional regression.
However, i have now realised i want to include a 9th variable within the overall dataset which is contained within each of the 6 individual datasets. How can i add this variable to my dataset?

Hopefully my question is clear-ish, i've tried to explain it the best i can
Thanks for any help in advance, Anya