New Zealand resident traveller departures from Dunedin Airport

The loss of information from the removal of the departure card means Stats NZ will no longer provide resident departure series.
From November 2018, resident arrivals is the only source of information for short-term travel of NZ residents.

New Zealand-resident travellers: people who live in New Zealand and are travelling overseas for less than 12 months.

http://datainfoplus.stats.govt.nz/Item/nz.govt.stats/f705ca38-ea6e-453f-b1d9-a95dc0fcaf59

A person may change their intentions after their arrival or departure, which may mean the recorded passenger type becomes incorrect. Stats NZ does not revise published statistics for such changes, but advises that the published figures remain a good indicator of trends in permanent and long-term migration.
Data is derived from a sample of records and hence may contain sample error. Caution should be used when using data with low cell values.
All figures for permanent and long-term migrants are actual counts (not derived from a sample). Arrival and departure totals for overseas visitors and New Zealand-resident travellers are also actual counts. More detailed data for overseas visitors and New Zealand-resident travellers, such as figures by country or travel purpose, are derived from a sample.

Before September 1997, NZ port data refers to the last port of departure from New Zealand. From September 1997, it refers to the New Zealand port of embarkation (port where passenger was processed by Customs).

From August 2016, international travel and migration data started being processed using a new, upgraded processing system. The new system uses improved methodology, which takes greater account of travellers' history in addition to intentions stated on the arrival and departure cards. It also makes greater use of automation in the processing and classification of passenger types. There were no revisions to the historical data with this system and methodology changes.

At URL provided, select 'Tourism > International Travel and Migration - ITM > NZ-resident traveller departures by purpose and NZ port (Annual-Dec). All variables were selected to produce this dataset.

International travel and migration statistics count passengers arriving into and departing from New Zealand. Passengers are split into one of three passenger types: overseas visitors, New Zealand-resident travellers, and permanent and long-term migrants.
Arrivals and departures of overseas visitors and New Zealand-resident travellers are key indicators of tourism and travel. Permanent and long-term migration is a component of New Zealand’s population change, along with births and deaths. Migration affects the composition of the population as well as population size.
International travel and migration statistics are based on electronic arrival and departure records for each international passenger, supplied to Stats NZ by the New Zealand Customs Service. These electronic records include flight and passport details, such as date of travel, date of birth, sex, and country of citizenship.