I see no reason for "3 Y axis for each year".
You would need one y axis data series for each year.
This requires a separate field for each year and the number of such series can't be changed as you add more years of data to your database.
Thus, you may want to set up a related table for your chart layout and use calculations/relationships to generate a set of Y axis data series for charting in your graph. This might enable you, for example to chart the "most recent 5 years" of data with one line for each year.
The trick would be figuring out the specifics to work with your particular data model and verions of Filemaker.
Why couldn't Filemaker simply allow a "by" option to split the x-variable into multiple series. I was hoping for that with FMP13 but no such luck it seems.