Pensions are contributed to and calculated very differently in different countries, so it's quite difficult to compare a single number, and you have to dig into it a bit more. I akso think that article must be looking at average pensions including occupational and state earnings- based pensions, because it's way off!!
I've put down more detail below for some of the countries here, just to show how misleading that table is. You do have to also consider salaries, to put the figures in context. And note that some countries give more to single pensioners, and less if you're a married couple- reflecting different living costs
UK Median gross/net salary £39k/£30k
Universal state pension: £12547
Netherlands Median gross/net salary £40k/£32k
£11600 if you are one of a couple, £17000 if you're single
Ireland Median gross/net salary £48k/£34k
Universal state pension: £13,500
Switzerland Median gross/net salary £90k/£67k
If single, the minimum is £14,650 after full 44 years of contributions on low earnings/contribution, going up to £29300 for the highest earnings/contributors
Married couples get 150% of a single person's pension: so £11000 each for minimum earners going up to £22000 each for maximum earners/contributions.
Several of the other countries work completely differently: they may be either based on your tax contributions or mandatory savings/investments but they are effectively based entirely on your lifetime earnings with no universal component. They additionally have a means-tested safety net/welfare
Sweden - 16% of your salary saved and 2.5% of your salary invested in funds of your choice
belgium 60% (single) to 75% (household) of your average gross career salary for a full 45-year career
Austria 80% of average lifetime earnings for those with 45 years of contributions, based on your 10 highest earning years