The Netherlands held a national parliamentary election on March 15, but did not release the official results until March 21. Turnout was 82%. Under the country’s proportional representation system, thirteen parties won seats. This article gives the details. The reason the official tally took so long is that all votes are counted by hand, rather than by electronic means.
Wikipedia gives the party names in English. https://en.wikipedia.org/wiki/Dutch_general_election,_2017
Imagine how nice our Congress would be if instead of Democrats, Republicans, and two independents, we were represented by 13 parties, ranging from Green, Constitution, Libertarian, to the Party for Socialism and Liberation, Modern Whig, and Prohibition.
Not saying all these parties would win seats, but I would much rather have a multi-party coalition system than the garbage we’re currently stuck with.
The votes are counted by hand at the polling station on election night. There appears to be a complete mistrust of anything electronic in the tabulation, but the polling stations are permitted to telephone the party breakdown after they make the count. This count is considered to be preliminary and unofficial. Distribution of seats in Parliament is based on the party vote, and fairly good estimates can be made based on this preliminary vote. But because all 150 seats are based on the proportion of the total vote, a complete tally is necessary for the final distribution. The separation for the final seats can be well under 1% of the vote received by the party.
In addition, the determination of which individual candidates are elected is quite complex. Parties provide ordered lists of nominees, but voters may also vote for an individual candidate, who can jump ahead of higher-listed candidates on the party list. The Netherlands now includes Bonaire, Saba, and Sint Eustatius in the Caribbean. At certain stages, the tally sheets must be personally carried to the higher levels. This may require officials to fly from the Caribbean to the Netherlands proper.
You linked to the site of the Electoral Council, and what they announced were the final results, in effect the final canvass. This was announced on March 21, 6 days after the election. The elected MP’s take their seat on March 23, two days later.
It may take months for a coalition government to be formed, since it will include at least four parties. The former coalition of two parties lost 47% of their seats (79 to 47).
An exit poll had the final seat tally for each party within a total of six seats. One party was projected to receive two more seats (16 rather than 14), one party one more (6 vs. 5), one party one less (19 vs 20), and one party two less (31 vs. 33).
By 11:00 pm, two hours after polls closed, projections based on actual ballots counted were within a total of six seats, with no party having a final error of more than one seat.
It is totally inaccurate to claim hand counting delayed the result.
The newly elected MP’s took office 8 days after the election.