NSC Interest Income Query - Kindly Advice

I invested in NSC 7 years ago. 

For the first two years (i.e. 1st & 2nd years) my total income was less than taxable limit and hence I did not file my IT Returns.

For the next 4 years (i.e. 3rd, 4th, 5th & 6th years) my total income was above taxable limits and I filed my IT Returns, showing NSC Interest Income earned for each year in Total Income for the Year.

Now for the last year (7th year) NSC got Matured, and I received the lump sum maturity amount.

My Query: For the purpose of Filing IT Returns in 7th year, should I show the NSC Interest Income Earned for the 7th Year alone, OR should I show NSC Interest Income Earned for 7th, 1st & 2nd years (i.e. NSC Maturity Interest LESS the NSC Interest already Reported). Kindly Advice & Help. Thanks.

Asogan