It depends on provider and geographical coverage. Let's take worldwide coverage (excluding USA, Caribbean, PR China and Singapore) for a male, age between 45-50 and it will be about USD 2'100.-/year. Same case for 55-60 = USD 3'600.-/year and when this person gets 65-70 he should calculate a minimum of USD 5'300.-/year. You can imagine that rates get insane once you are 70+. Mentioned tariffs are for a full-service private health insurance with an annual per-case excess of USD 500.- .
Note that this varies greatly from one provide to the other.︀ Mentioned rates are on the lower end, you will not get BUPA insurance for these︁ tariffs.
Note that this varies greatly from one provide to the other.︀ Mentioned rates are on the lower end, you will not get BUPA insurance for these︁ tariffs.