Generating sequential unique ID based on other value and date

Hello all,

After googling for an answer for several days, I thought I'd try my luck at the excel forum.

I'm trying to set up a claims registration form using excel where column A is the manually input shipping reference, and column B an auto-generated sequential claim ID based on the shipping reference and on the current year. One shipping reference can have multiple claims so in case the shipping reference is the same the claim ID should be the same as well.

This is what I am trying to achieve:

Shipping ref. Claim ID
ABC-123 20160001
ABC-124 20160002
ABC-124 20160002
ABC-125 20160003

From looking around I guess that I need a formula including some IF and COUNTIF statements and maybe a reference to a calendar, but honestly, I can't really figure it out so any advice would be greatly appreciated.

Cheers