2016 NSW population and household projections

Interesting to click the Tabs of different council areas and see the project population growth projections over 5 years and so on. I was mainly looking at Sydney Metro LGA

How accurate is this data? How accurate were projections. In my research I found the ABS vs Border force numbers shows that ABS data is underestimated in tersm of Migrations data.?
Here is the extract.
"
Population projections show that NSW will grow to 9.9 million people by 2036.

The Department of Planning and Environment uses population and household projections to help plan for service and infrastructure delivery for the community.

These projections give us a framework for assessing future needs for residential and commercial land, housing and public utilities.

The 2016 NSW population and household projections show how our population is expected to change over the coming years. The projections show the expected impact of these changes on households and the implied demand for housing.

These projections are not targets. Projections are based on assumptions that take into account trends for births, deaths and migration.

Projections can change due to factors such as migration levels, new technology and social attitudes to different living arrangements. "

Population projections - Department of Planning and Environment

 

What was the difference in numbers you have found?