Gas water heaters sold in New Zealand

Energy consumption: amount of energy input required to raise the temperature of 200 litres of water from 15°C to 60°C every day. The lower the number, the more energy-efficient it is.
Sales weighted: weighted average of the units' energy consumption. This average is weighted proportionally to the sales of units.
Average nominal hot water delivery: volume of hot water delivered per minute.

Annual energy consumption is based on assumed yearly usage.
The average is sales-weighted, which means it depends on the energy efficiency of units that were actually sold.

https://www.eeca.govt.nz/standards-ratings-and-labels/equipment-energy-efficiency-programme/about-the-e3-programme/

At URL provided, select the '2023 Gas water heaters sales and efficiency data' Excel file.
This spreadsheet was reformatted for easier processing.

Through the Equipment Energy Efficiency (E3) Programme, New Zealand and Australia develop common energy efficiency measures to regulate the energy performance of products in both countries.
Suppliers of products regulated under the E3 Programme provide Energy Efficiency and Conservation Authority with annual sales data for the period of 1 April to 31 March. This is used to help measure the shift in product efficiency over time and to calculate the energy savings to date from these improvements in energy efficiency.

The Equipment Energy Efficiency Programme is run by the Commonwealth state and territory and New Zealand governments working with industry to drive improvements in the energy efficiency of appliances and equipment to save households and businesses money on their energy bills reduce energy use and reduce emissions.

The measures developed through the E3 Programme are minimum energy performance standards (MEPS) and the Energy Rating Label.