Urinary Sodium and Potassium Excretion, Mortality, and Cardiovascular Events
tl;dr
All cause mortality lowest at 5g/day (baseline). At 2g/day, all cause mortality 2x baseline. At 10g/day all cause mortality 1.2x baseline
The graphs, especially Figure B at https://www.nejm.org/doi/full/10.1056/nejmoa1311889 are a masterpiece of data visualization. IANAD, but don't restrict salt below 5g/day unless you are asked to by your medical professional.