Han, according to the MOM data, 790 aeronautical engineers are represented in the survey. The MOM report also mentions that the wage data come from CPF, so I think there's much accuracy - at least it's better than surveys that ask people to fill up forms.

btw, the mean (=average) basic pay of aeronautical engineers is $4,313. At the 25th-percentile, it's $3,090. Median is $4,031, while the 75th-percentile aeronautical engineer makes $5,063 (which is the value I used in the ranking).

Since the mean is higher than the median, we can infer that the pay distribution is skewed toward the higher income earners.