Comparatives for tax thresholds

What was the requirement for submitting tax return for the following years. In terms of the threshold. 2011/12
2012/2013
2013/2014
2014/2015 = R350000

The threshold is ONLY applicable if you have one employer for 12 months and receive one IRP5 with just a salary and no other deductions like medical or any other income whatsoever. Literally a salary with source code 3601 that's it. We advice filing anyway as SARS are known to ask for tax returns in years even when they say filing isnt necessary. In prior years the supposed threshold was R250 000.