I came across an interesting generalisation concerning the use of the apostrophe with plurals on the website  of the Apostrophe Protection Society, quoted in Beal (2010):

3. Apostrophes are NEVER ever used to denote plurals! Common examples of such abuse (all seen in real life!) are: 1000’s of bargains here! which should read 1000s of bargains here!

The following comment is added:

We are aware of the way the English language is evolving during use, and do not intend any direct criticism of those who have made the mistakes above. We are just reminding all writers of English text, whether on notices or in documents of any type, of the correct usage of the apostrophe should you wish to put right mistakes you may have inadvertently made.

As a English secondary-school teacher in The Netherlands, I felt intrigued by this, and decided to offer the following comment: firstly, not everybody that doesn’t precisely follow the rules outlined on the website is ‘illiterate’ or ‘stupid’. Secondly, it is not a matter of life and death if somebody gets their apostrophe’s wrong, you yourself had to learn it as well. Thirdly, life isn’t all that black and white. These generalisations seem to have a lack of scholarly nuance.

Continuing on my third point, I will now provide a different  explanation, proving any claim I make, in contrast to some who merely rely on their instinct to create a generalised ‘rule’. I now quote An English Grammar for Students in Higher Education (Koning & van der Voort 1997:165) on correct ways to form a plural:

Plural formed by ’s

[W]ith … numerals the plural may be formed by ’s, but s is more common: The 1980’s (but usually 1980s).

In addition, Practical English Usage (Swan 1995:465) also points out the following option:

Apostrophes are used in the plurals … of numbers. It was in the early 1960’s  (More usually: … 1960s).

There’s no such thing as a breakdown of society (as Beal comments on) when someone puts an apostrophe s after a numeral. Not intending to offer any direct criticism of those who have carefully compiled the list of language abuse, I would like to claim that it would be too easy to dismiss other variants, since English is and will always be the language of exceptions.

References

Koning, P.L. & Voort, van der, P.J. (1997), An English Grammar for Students in Higher Education. Groningen: Wolters-Noordhof.

Swan, M. (2005), Practical English Usage. Oxford: Oxford University Press.

Joan Beal (2010), “The grocer’s apostrophe: popular prescriptivism in the 21st century”. In English Today 102. 26/2, 57-64.