Our revamped Household Labour Force Survey now collects information on union membership and on types of employment agreement, which sounded interesting, but when I went and downloaded the HLFS Excel files (here) the info wasn't there. So I got in touch with Stats and their helpful chap Ken Joe told me two things.
One was that Stats had put out a specific article about these very topics on August 25 (which for some reason I'd missed, and I may not be alone, as there doesn't seem to have been much media coverage of it). And the other was that the data is available, though not where I went searching for it first. If you'd like to look it up for yourself, it's on Infoshare: go to 'Work, income and spending', then 'Household Labour Force Survey' and scroll down to the P's where you'll find 'Paid employees by type of employment agreement' and 'Paid employees by union membership'.
The article said that "Statistics NZ collected this information only twice previously, in the Survey of Working Life 2008 and 2012": they didn't compare the new HLFS data for June 2016 with the previous years' estimates, however, so I've dug out the earlier data. If you missed the Stats release (like I did), and would like the wider historical sweep (such as it is), here is the result.
It's not a pretty picture if you're sympathetic to organised labour. The absolute numbers probably show it even more clearly: in 2008, an estimated 525,000 people were members of a union; by 2012, that had dropped a bit, to 501,000; but it's slumped in the past four years, to 379,000. The drop in numbers of people on collective contracts isn't as dramatic (467,000 to 440,000 to 410,000) but it's still substantial. If the declines continue at these rates in coming years, unions face an existential threat.
Especially if anything arises to weaken membership in the sectors where they are still important. As Stats said, "Some industries are far more unionised than others (see figure 2). Over 4 in 10 employees in both health care and social assistance (43.5 percent) and education and training (42.2 percent) belonged to a union. Given the size of these industries (231,100 and 203,500, respectively), this means half (49.2 percent) of the 379,300 union members worked in only two industries".
Here's that figure 2 Stats was talking about.
Outside what are largely public sector industries, union membership has fallen to insignificant levels - even in sectors such as finance, where unions were once a reasonably large player, but are now down to 10% of the workforce in the sector.
Originally I'd set out to look up some data releases I'd unaccountably missed (I'm on Stats' distribution lists for pretty much everything they put out), and not to do any policy research into the role of unions in a modern economy, and I'm not going to start now. All I'd observe is that the sharp membership fall of the past few years is a lot faster than I intuitively (econospeak for "at a total guess") would have expected to see, and I'd guess there are some worried people around the tables in unions' head offices.