Does the 27.5% of income you can put into a pension fund only mean income you have earned as a wage?

I am self employed and only earn about R12000 per year. However I earn about R200000 per year in interest from savings accounts. Can I put 27.5% of my total income (Earnings and interest) into a pension fund per year or only 27.5% of the money I earn through working?

The law was unclear on this previously, but now has been amended to include interest and other passive income which became effective from 1 March 2016 so you would be able to include that in the calculation.