The number of millionaires in the Netherlands was up again at the start of this year, with 452,000 households now owning assets worth at least €1 million, according to new figures from national statistics agency the CBS.

That is 17,000 more than a year earlier and means that 5.5% of all Dutch households can now be classed as millionaires. This does not mean they have €1 million in the bank, but that their total assets – including the value of their home minus any mortgage debt – amount to at least that much.

Millionaires are most heavily concentrated in the provinces of Noord-Holland and Utrecht, where around 7% of households are worth at least €1 million.

In the towns of Bloemendaal and Laren, both in Noord-Holland, roughly one in three households are millionaires. Other wealthy towns include Blaricum (25%), Heemstede (24%) and Wassenaar (23%).

At the other end of the scale, fewer than 4% of households in Groningen, Flevoland and Limburg qualify as millionaires. The towns of Brunssum, Heerlen and Kerkrade in Limburg, along with Nissewaard in Zuid-Holland and Den Helder in Noord-Holland, have the fewest millionaire households relative to their population.

Millionaires tend to hold a far smaller share of their wealth in their homes than the average Dutch household. The home, after subtracting mortgage debt, makes up around a quarter of their assets, compared with three-quarters for non-millionaires.

For the wealthiest households, significant business interests and company assets play a key role, accounting for nearly 40% of total wealth. Among the richest millionaires – those with assets over €10 million – two-thirds of their wealth comes from business ownership.

The millionaire population is also getting older. Around 40% now receive most of their income from a pension, compared with 26% of non-millionaire households. Of those who still work, 55% are self-employed, though this is down on 2014, when more than 70% of working millionaires were business owners.

Since 2011, the number of millionaire households in the Netherlands has nearly tripled – from 170,000 to more than 450,000.