A century of changing transport spending

Via Donal Curtin, I got wind of a fantastic Statistics NZ visualisation of changes to the Consumer Price Index over the last century. The Consumer Price Index, or CPI, is a tool that statistics agencies use to track inflation over time. It tracks changes in prices in the goods and services that households purchase.

This is not as simple as it seems at first, because people’s consumption habits and choices change over time. For example, one hundred years ago New Zealanders weren’t eating many avocados (not cultivated here until the 1920s), buying many laptops (not invented yet), or getting their legs waxed (not even considered at that time). So Statistics NZ has to periodically update the CPI by introducing new products to the “basket” and removing others.

As a result, CPI basket changes are a good way of looking at our changing consumption habits over time. Some of the changes are amusingly bizarre – for example, what was happening during the five year period from 1988 to 1993 when waterbeds and wine coolers were briefly a part of the CPI basket? (Younger readers might not want to think too hard about that one.)

Here’s are the transport goods and services that have been added and removed over the last century. They tell us quite a bit about how our travel behaviours have changed:

A few things strike me as notable:

• Compared with other CPI areas such as leisure, home, and food, which can be seen on Statistics NZ’s website, transport has experienced relatively little change over the last century. The number of products introduced and removed is relatively small. The technologies that were available a century ago – trains, buses, cars, bicycles – are still useful today.
• Tram fares were introduced to the CPI in 1924, as cities grew rapidly around tramlines, and removed in 1965 following the ripping-out of the tram lines.
• However, other public transport technologies have stayed relevant – train fares were added 1924 and bus fares in 1949. Urban ferry fares are the newest addition in 2014, reflecting rising patronage in the largest cities.
• The 1950s were a big decade of change, with motor vehicles and associated goods (petrol, driver licences) added to the CPI. Bicycles were also added!
• Kiwis took to the air in large numbers in the 1970s, with domestic and international air fares added in 1974 and 1980, respectively.
• The 1970s oil shocks led to a few changes to the CPI. 1974 saw the introduction of motorcycles, a fuel efficient option for many young New Zealanders. It also led to some short-lived changes in the fuel consumption of the car fleet – in 1988, diesel, LPG and CNG were added. But LPG and CNG were removed before too long, as lower petrol prices in the 1990s reduced the need for alternative fuels.
• Technological changes and a return of high oil prices resulted in the introduction of hybrid vehicles in 2011.

Who said statistics is boring? There’s an awful lot of social history compacted into a dry figure like the CPI!

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