anchor.diff:  "EST","EE","Estonia",2010,1,1
   "EST","EE","Estonia",2011,0,0
   "EST","EE","Estonia",2012,4,0
  -"EST",NA,"Estonia",2013,NA,0
  +"EST","EE","Estonia",2013,NA,0
   "FIN","FI","Finland",1975,NA,NA
   "FIN","FI","Finland",1976,3,3
   "FIN","FI","Finland",1977,2,2
  
positive.code: "BEL","BE","Belgium",2010,1,0
  "BEL","BE","Belgium",2011,3,3
  "BEL","BE","Belgium",2012,2,2
  "BEL",NA,"Belgium",2013,NA,1
  "BGR","BG","Bulgaria",1975,NA,NA
  "BGR","BG","Bulgaria",1976,NA,NA
  "BGR","BG","Bulgaria",1977,NA,NA
  
negative.code: "LTU","LT","Lithuania",2010,4,2
  "LTU","LT","Lithuania",2011,3,1
  "LTU","LT","Lithuania",2012,2,0
  "LTU","LT","Lithuania",2013,NA,3
  "LUX","LU","Luxembourg",1975,4,4
  "LUX","LU","Luxembourg",1976,3,3
  "LUX","LU","Luxembourg",1977,2,2
  