Tableau: Dealing with Date values

Im a noob at tableau. I have a quick question

I have data that doesn't explicitly list the date. (There is no column labelled "date" )

However there are columns with the following headers:

"Income 2015", "Income 2016", "Income 2017" (the cells within these columns have financial data and do not have a "date")

Is there a way I can write a rule or do manually that will allow me to create dates (by year) based on these header names?

And then use the newly created dates to map to their respective columns?

So lets say I create the date with a value of 2017. Could I map this date to the column "Income 2017"? And make all the cells within this column also map to date 2017?

I hope this makes sense. Its been killing me trying to figure out if this is possible.

Thank you,