Here are the number of suicide rate for the age 65 of older per ethnic group :
Non-Hispanic Whites — 15.8 per 100,000
Asian and Pacific Islanders — 10.6 per 100,000
Hispanics — 7.9 per 100,000
Non-Hispanic Blacks — 5.0 per 100,000
So the one that has the lower risk of suicide would be : Non-Hispanic Blacks
hope this helps