This stabilisation happened as inequality in other countries such as the United States deteriorated.
Despite that relative improvement, New Zealand is still a relative outlier, with much wider inequality than it had back in the 1970s when our society was less exposed to the world. We saw ourselves as simple, clean, honest and free of corruption.
It is now much easier to move money in and out of the country. Many more of the population have grown up or lived and worked in societies where corruption is a more normal part of life.
There is now much greater variety in incomes and the temptation to use money or make money in corrupt ways is much greater.
Other countries with similar Gini levels to New Zealand include the likes of Italy, India and Egypt.
Yet New Zealand is ranked alongside Denmark as the least corrupt nation on the planet by Transparency International. That's quite an achievement given Denmark, Finland, Sweden and Norway all have Ginis that are significantly lower than ours.
New Zealand's reputation is both an opportunity for us to advertise ourselves as a great place to do business, but it also has a value that has to be protected.
Now the finance company crisis is over and financial market regulation has been modernised and toughened, there may be a temptation to be complacent.
But the Serious Fraud Office reports it is busier than ever investigating all sorts of cases of corporate and government fraud. An OECD team specialising in foreign bribery has visited New Zealand in recent months to assess its vulnerabilities, particularly as its connections with North Asia, South Asia and Africa are growing.
The SFO faces pressure to scale back its operations in the wake of the end of the finance company prosecutions, but that creates a risk.
Just as New Zealand should consider investing to protect its 100% Pure environmental brand, we should be prepared to spend on preventive maintenance on our reputation as the least corrupt nation in the world.
That reputation has a value and it should be protected from the natural pressures of the growth of our inequality since those simple times of the 1970s and early 1980s.