The rate of (mental) decline was reduced by 10 percent to 13 percent per year among persons who consumed one or more fish meals per week compared with those with less than weekly consumption,
We found that people who ate one fish meal a week had a 10 percent slower annual decline in thinking, ... Those who ate two fish meals a week showed a 13 percent slower annual decline.
Those who ate two fish meals a week showed a 13 per cent slower annual decline.