You are given the following claim count triangulation, providing the number of claims occurred in each policy year and are reported within a certain number of development years.

Development Year 0 1 2 3 4 5 6 7 8 9 Policy Year 2004 4 9 9 10 10 10 10 10 10 10 2005 4 8 9 9 9 9 9 9 9 2006 4 6 7 8 9 9 9 9 2007 6 14 18 18 18 18 18 2008 4 9 10 11 11 11 2009 5 8 10 11 11 2010 1 3 6 7 2011 5 9 11 2012 1 6 2013 1 Using the chain ladder method, and assuming 12 months of development are available for 2013:

a. Estimate the number of IBNR claims for each policy year.

b. Without doing any further calculation, comment on the uncertainty of the estimated IBNR for each policy year.

c. Show how your answer would change if only 9 months of development were available for 2013.

State explicitly any other assumption you need to make.