The denominators used for calculating population rates in this report were derived from Statistics New Zealand census population data matching the year of the data. For District Health Board (DHB) analyses, interpolated mid-year populations have been used as the denominator populations.
For most rates for health effects, 95% confidence intervals have been presented to indicate the uncertainty in the value. The 95% confidence interval represents the range within which the true value is likely to fall 95% of the time. When the 95% confidence intervals of two rates do not overlap, the difference in the rates is said to be statistically significant. It should be noted that in this report, the word ‘significant’ indicates statistical significance.