"Whether having had a long training period in tertiary institutions as a younger person or having learned the ropes on the job since leaving school, the 40s is the time when most working people are fit, well, energetic and highly motivated to meet family and domestic commitments," he said.
"Young children and mortgages do wonders for motivation. The workplace is also able to provide the environment and challenge to meet and realise personal goals."
The average earnings of a New Zealander is recorded at $1086 per week.
The data, compiled of average earnings for both men and women aged 15 through to retirement age, breaks up weekly earnings according to age bands.
Earners aged between 15 and 19 earn an average of $356 per week. Those aged 20 and 24 earn $691 per week and those 25 to 29 earn $970 per week.
In their 30s, the average income of a New Zealander grows steadily and peaks between the ages of 40 and 45. Once you hit the 50 years-old mark, however, data reveals earnings decrease with the average weekly income dropping to $1292 and a further $148 for those aged 55 to 59.
Earners aged 65 and older earn an average income of $825 per week, data reveals.
Pettersen said this indicates there are a number of people in their late 60s, 70s and perhaps 80s who are still working, employed in low-paying jobs.
"These jobs are probably not the ones that they have spent most of their working life in. Hence the lower rate," he said.
Strategic Pay chief executive John McGill believes the income dip can be attributed to those aged 60 and above choosing to work less.
"My view is that individuals are starting to pull back in terms of hours, opting to work less onerous roles, and perhaps no longer able to get the higher paying positions in competing against younger applicants. It may be that some have not updated their skill sets (struggle with technology for example) and this may disadvantage them as well," McGill said.
Teens between the ages of 15 and 19 earn almost double their weekly income to $691 per week after a few years between the ages of 20 and 24.
According to the DAVOS 2017 Global Wage calculator New Zealand sits considerably ahead of the world in terms of the average annual wage of NZ$29,181, taking into consideration the earnings of under-developed countries.
Within OECD countries only, New Zealand earnings sit within the top 10.