Small businesses depended heavily on factors outside of the market's control, especially the capability of the business owner.
"As much as it's about the market, it's about how you work in the market. How well you do depends on the energy put in."
It was difficult to get a decent grasp of how successful those 37 per cent had been, given there was no detail about how much their revenue had increased by, Mr Norton said.
"It could have been by $1."
Nationally, 39 per cent of New Zealand's 460,000 small businesses increased their revenue in the year, compared with 30 per cent in the previous year.
MYOB chief executive Tim Reed said it was heartening to see small businesses in such good shape. "What's particularly positive is that growth is no longer confined to just the two largest centres, with the rebuild in Christchurch and the expansion of Auckland no more the only drivers of the economy," Mr Reed said.
The whole country was enjoying "solid levels" of economic growth.
Christchurch still led with 51 per cent growth in the 12-month period but regional New Zealand was not far behind - with Waikato and the Bay of Plenty experiencing higher growth than the national average.
Only the Wellington region experienced subdued revenue.
The most significant improvements were in the retail and hospitality sector, followed by agriculture, forestry and fishing.
Forecasts for the coming year predicted similar levels of growth, with 38 per cent anticipated to increase revenue and 43 per cent to maintain currently steady levels.
"Over the coming months, many business operators will be looking to consolidate gains, and invest more in their people and systems ... so they can enjoy these benefits for some time to come."