I believe 2000's index is 99. The pattern is 99+3=102 which is 2001's index. 102+4=106 which is 2002's index. and you can see that pattern continues all the way up to 2006. see if you cannot figure out the percentage portions though, before looking for a little more help. Remember the definitions of what a percentage is. 3 is 150% of 2...aka 2*1.5=3.