Car Insurance premium up 20%

I have used USAA for my auto insurance for 11 years and have been reasonably satisfied with them.However this morning I got an email from them informing me my auto insurance rate is going up by 20%, TWENTY PERCENT!I have no traffic violations, speeding tickets or other violations and the only time I've used them was 9 years ago with a car tow.My credit score is 700+ BUT I am turning 75 years old this month and that has to be the reason for the huge rate increase.Although I've been loyal to USAA I'd like some other auto insurance companies...