You should simply state your current salary and age for your question. What is the point of mentioning that you are a poly graduate? To justify your current salary? Are you going to be complacent if majority here say that it a good figure?
Mr Hitler,
I would think that TS mentioned his educational background as a baseline reference to his salary.
If someone with PSLE or O levels earn 4k after working for 16 years then he would be above average
If someone with Diploma or equivalent earn 4k after working for 16 years then probably he is average.
If someone with degree or higher earn 4k after working for 16 years then maybe is below average.
I don't think TS want to how lian or what.