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.- .What are typical private health insurance rates ?
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 these tariffs.