As an alternative to the census we can determine someone’s sector of employment from IRD records. This has the advantage of being trackable over time and providing detailed information about income. IRD records do not have any information about a person’s occupation, however. This limits us to defining a workforce based on their industry only. We can use income thresholds to select the less casual elements of a workforce. For example, we may include only those who earn more than $2500 per month in a sector.