If you want to avoid attacks from wildlife you should walk around dressed up like a Vacuum Cleaner to ward off attacks from dogs. I looked it up and found a stat that showed there have been 137 shark attacks in Hawaii since 1837. Not deaths, just attacks. That is less than 1 a year over 180 year period. Dogs attack thousands of people every year.
Incidents List
In 2019 there were 13 shark attacks, 10 of which the activity was swimming with no surfboard/paddle board to be accidentally confused with. That's a lot more than your 1 per year estimate.
Sharks in Hawaii - The Good, Bad, and Ugly - Living in Hawaii - Moving to Oahu, Maui, Kauai, Big Island
I think the above write-up is well written and informed. He makes some good points about "why sharks attack people"