In September, 90,213 patients fell within the timescale, equal to 90.8%. However, 9114 patients had to wait longer.
The Scottish Government target came into force on December 31 last year and has been met each month since on average across the country.
Despite the overall figure, three health boards failed to hit the target in September.
Ayrshire and Arran recorded 89.6%, Lothian saw 87.1% and Forth Valley 83.1%.
Health Secretary Alex Neil said: "Quick access to treatment, delivered as locally as possible, is what patients want.
"I am proud to say that NHS Scotland is continuing to deliver on the target.
"We are continuing to work closely with those health boards who are not meeting the target to ensure future compliance.
"It is important to remember just how much progress has been made.
"In 2007 over 29,000 people were stuck on hidden waiting lists and the maximum wait to get an appointment was six months.
"Now, patients in Scotland are being treated quicker than ever."