Analytics Software

I have a business request where the client is asking for a year over year percentage comparison for multiple years

So for example

          Applications

2015     5

2014     10

2013     22

So in year 2015 we can see that applications is currently down (5-50/10 - [New-Old/Old] by -50% compared to year prior

In year 2014 we are down -55%

Ultimately I wanted to display the following

          Applications

2015     -50%

2014     -55%

2013    

I have an idea of how to do this for a single year, where a presentation variable is fed in then I can just do this year minus previous year.

I was wondering, how can I do this calculation or presentation in OBIEE? Can this be done within answers? Or does something need to be done in the RPD?