Sir Liam Donaldson, the UK's chief medical officer, reports the swine flu pandemic is "considerably less lethal" than feared, according to the BBC. A study led by Sir Liam found a death rate of just 0.026% in those infected, the British Medical Journal reported.
In the US, approximately 2,000 lab-confirmed deaths have occurred from swine flu, with a CDC-estimated 20,000,000 swine flu cases. This translates to 0.01% mortality. My guess is that there were somewhat more deaths in the elderly, but also many more cases--or the epidemic would not now be dying out. So 0.005% to 0.01% seems a reasonable mortality estimate. Furthermore, now that we understand how to treat the serious cases better, mortality rates should drop over time.
UPDATE: Just-released modelling estimates from CDC suggest 50 million Americans have been infected, and 10,000 have died from swine flu. This yields an estimate of mortality congruent with the UK estimate of 0.02%.