How to strip out FX to get to "true" sales?

I'm analyzing a global company that sells in multiple currencies and am trying to pull out the organic sales independent of FX effect to get to an idea of the company's true operational sales generation/growth.

Each annual report has CY sales compared to prior year sales adjusted for FX translation (i.e. it breaks out "Organic Sales", FX Translation, and Reported Sales to get to a prior year Organic Sales figure in CY terms). Obviously in each report CY Organic Sales has no translation because it's already in CY terms.

Each year has this laid out. However obviously when you go between reports the number for organic sales in 2015 in the 2015 report will be different than 2015 in the 2016 report because in 2015 it's "actual" and in 2016 it's adjusted to reflect 2016 rates. Reported sales doesn't change.

So if I have the 2015 and 2016 report, I have three years worth of data (2014-2016). In the 2015 report, it shows 2014 in 2015 terms and 2015, and in the 2016 report it shows 2015 in 2016 terms and 2016.

My question is, how do I get 2014 to be equivalent to 2016 so I can present the organic sales in a single table and have them comparable?

I don't have the sales by currency which I think would make this easy, and this company sells in like six different currencies.