Why Singaporeans Leave Singapore

Official statistics on this don't seem to be available (a report on a 2015 IPSOS study doesn't gie many details), though I know I've read news articles referencing replies to the Singapore Police Force's Certificate of Clearance (required when applying for permanent residence/citizenship in another country).

One could do worse than look at the options given on the form for applying to renounce it ("What are your reasons for having emigrated or wanting to emigrate?"), of which one is asked to rank the top 3:

High cost of living in Singapore
Singapore is too regulated and stifling
Better career / business prospects overseas
Better and less stressful education opportunities for your children
Prefer a more relaxed lifestyle
To be united with close family members who migrated earlier
Do not want your son/s to serve National Service
Retirement aboard
Marriage to a foreign national
Uncertain future of Singapore

Too bad we don't know how often each item is selected (or the priority given to each). Then again, given the culture of fear in Singapore, even the official data might be suspect.

Anyhow, in addition to this one is asked why one is renouncing Singaporean citizenship. In addition to the above, there are the following options:

To take up citizenship of another country
To take up permanent residence of another country
To withdraw CPF funds

So presumably there're countries where in order to get permament residence, you need to renounce your citizenship of another country.

Curiously, in order to renounce citizenship, men but not women need to give their education and employment history and family background. Whereas it seems married women (but not married men) must produce their marriage certificates.