What if someone told you the South Island's food bill is $15,305? You'd probably think: per household? Per person? For what period?

None of those. That number is an index. And it tells a story about your wallet that fifty years of shopping can't hide.

In 1975, Stats NZ set the South Island food price index at a baseline. Call it 100 points, like the start of a scoreboard. Every year since, they've tracked what happened to the cost of bread, milk, vegetables, meat. Everything in your trolley. By 2024, that index reached 15,305.

Think of it this way: if your weekly grocery shop cost $50 in 1975, the same basket of food would cost you roughly $7,650 today. The index doesn't measure what you actually spend. It measures how far your dollar has fallen.

The trajectory is what matters. For four decades, the index climbed steadily but slowly. Then 2020 arrived. In that year, the index sat at 12,509. By 2024, it had jumped to 15,305. That's a 22% rise in four years.

Compare that to the previous four-year stretch, 2016 to 2020, when the index rose just 6%. The last four years delivered nearly four times the food price inflation of the four before it.

Here's what that looks like in a South Island kitchen. A family spending $250 a week on groceries in 2020 would need $305 a week in 2024 to buy the same food. That's an extra $2,860 a year. For doing nothing differently. For buying the same items in the same quantities.

This isn't about inflation as an abstract concept. It's about whether your pay rise kept up. Spoiler: for most Kiwis, it didn't. Wages across New Zealand rose roughly 15% between 2020 and 2024. Food prices rose 22%. The gap between those two numbers is why your grocery shop feels heavier than it used to.

The index keeps climbing, but the pace matters. Between 2023 and 2024, it rose just 1.6%. That's the smallest annual increase since 2020. The spike is slowing. But slowing isn't the same as reversing. Your trolley still costs 22% more than it did four years ago, and that's not coming back.

So what does $15,305 buy you? Nothing. It's not currency. It's a reminder that the price of feeding yourself has climbed further and faster in the last four years than in any comparable stretch in recent memory. And your wages didn't keep pace.

(Source: Stats NZ, food-price-index-regional)