There were 32 strikes in the Netherlands in 2017, seven times the number in the previous year and the highest in 29 years, the national statistics office CBS reported on Tuesday.

A total of 306,000 working days were lost due to strikes last year, compared to just over 19,000 in 2016. This was the highest number of working days lost through strike action in 20 years.  In total, 147,000 people downed tools at some point in 2017.

The industrial and transport sectors accounted for 13 and 12 of the strikes, most of which arose from a conflict over pay and conditions contracts, the CBS said. Holland Casino, KLM, Jumbo supermarkets and Unox were among the companies hit by strikes last year.

The biggest strikes involved primary school teachers, who are campaigning for more pay and better working conditions. Both the primary school and regional transport campaigns have continued into 2018.

‘We’ve noticed that people are fed up with shareholders profiting [from the economic upturn] but not themselves,’ Han Busker, head of the biggest Dutch trade union federation FNV told broadcaster NOS. ‘And that will continue throughout the Netherlands this year.’

The CBS published the results on May 1, celebrated as International Labour Day and a public holiday in many countries, but not the Netherlands.