# Building a forecast model based on past year data in R

I am attempting to build a model to forecast attendance in a given week in the current year based on this year's attendance values up until the present, and data from two previous years. My data looks like this:

   Week 11-12 Cumulative ADA    12-13 Cumulative ADA    13-14 Cumulative ADA
1    0.9941                  0.9941                  0.9914
2    0.9907                  0.991                   0.989
3    0.9888                  0.9888                  0.9879
4    0.9877                  0.987                   0.9869
5    0.9869                  0.9865                  0.9867
6    0.9862                  0.985                   0.9859
7    0.9856                  0.9842                  0.9857
8    0.9856                  0.984                   NA
9    0.9852                  0.9839                  NA
10   0.9848                  0.9834                  NA


Any guidance on how to predict the three NAs based on the past two years data and this year's values would be much appreciated.

Thanks!

• check out the forecast package - it's great. – Fernando Oct 16 '13 at 14:17