But the numbers also revealed something new — Pakeha children's reading skills are also falling. In fact, Pakeha literacy slid most steeply, down 13 points to an average score of 545.
At the end of a period of intense focus on numeracy and literacy, overseen by the former Government as part of its National Standards regime, this can only be seen as an own goal.
Naturally, the new Government was quick to blame National Standards, with its heavy testing and increased paperwork, for the results.
But that appears to only be one potential part of the problem. While Pirls (Progress in International Reading Literacy Study) did not identify drivers behind the results, it did give factors linked to the scores.
Marks were likely to be worse if a child was frequently absent from school, or their school had a low socio-economic roll, it said.
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It also had data about the children who took the survey. New Zealand 10-year-olds were more likely to be bullied, hungry or lack sleep. They were also more likely to be in classes streamed by ability.
Everyone with a stake in the matter had their own opinion.
Some said parents were spending too much time on phones, and not enough talking to their children.
Others will blame today's open classrooms, so-called Modern Learning Environments, for creating too much distraction.
The list seems endless, but the solutions few.
Perhaps one of the most interesting responses came from academic Tom Nicholson, who noted that England's (previously declining) reading performance had increased every year since 2006, when it started teaching phonics — teaching how letters sound so children can "decode" new words.
He said most NZ teachers still used the "whole language" approach as taught by our flagship Reading Recovery programme, encouraging children to work out a new word from its context.
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Nicholson has spent his whole career studying the issue, and previously noted it has been 30 years since there was major professional development for teachers — when Reading Recovery was implemented.
"Since then we have made new discoveries ... it is time to do it again, to redesign the literacy that is taught in our schools so that it works for the poor, the strugglers, and especially for Maori," he wrote.
Nicholson may not have the only bright idea. Just as there are many causes, there are likely to be many solutions.
But he's right about one thing — it is time to take a serious look at our literacy issue and ensure all our children are learning to read.