Why did workplace injuries among New Zealanders aged 90 and over suddenly drop by more than half in 2022?

For years, the numbers climbed steadily. In 2020, ACC recorded 28,491 fatal and serious injuries for people in this age bracket. In 2021, that rose to 29,499. Then, between 2021 and 2022, the figure collapsed to 12,597. It's stayed there ever since: 12,672 in 2023, 12,225 in 2024.

This isn't a story about octogenarians suddenly becoming more careful on work sites. The 90-and-over cohort represents New Zealand's most vulnerable workers and volunteers: people still active in their communities, still contributing, still getting hurt doing the things they've done for decades.

The most likely explanation sits in how ACC categorises these injuries. A methodological change, a reclassification, a shift in reporting thresholds. Something changed in the counting, not necessarily in the breaking.

But here's what the data does tell us with certainty: even at the lower count, more than 12,000 people aged 90 and over suffered injuries serious enough for ACC to classify them as fatal or severe in 2024. That's one in every five New Zealanders in this age group, given there are roughly 60,000 people 90 and over in the country.

These aren't minor slips. ACC's "fatal-serious" category captures the injuries that fundamentally change lives or end them. Falls from height. Vehicle accidents. Crushing injuries. The kind of harm that sends a 92-year-old to hospital and means they might not come home the same person.

The 2022 drop matters because it obscures a trend. When the baseline halves overnight, you lose the ability to track whether things are genuinely getting better or worse. Is 12,225 in 2024 an improvement on the pre-2022 trajectory, or a plateau? We can't know, because the measuring stick moved.

What we do know: New Zealand still has thousands of people in their 90s getting seriously hurt each year. Some will be farmers who never stopped working the land. Others will be volunteers at community centres, board members at marae, people who refuse to stop contributing just because they've hit nine decades.

The data from 2005 shows a similar figure: around 12,000. Which means either we've made zero progress in 19 years at keeping our oldest citizens safe, or the 2020-2021 numbers were capturing something the current methodology misses.

Either way, 12,225 people in their 90s suffering fatal or serious injuries in a single year deserves more than a footnote in a dataset (Source: Stats NZ / ACC, fatal-serious-injuries).