They're pretty close to synonyms in my and other people's understanding [1,2], but I would be unsurprised if some countries defined them differently. Edit: I've since realised from reading my own links carefully the labour force participation rate is employed + unemployed (looking for work) / working age population. Employment rate is employed / working age population. So I think I was right with saying employment rate initially : )

The OECD chart linked (if you play with the sliders) shows that both are increasing globally. I know that in the UK the employment rate is at an all-time high [3].

Your link seems like it might be using a strange measure of employment [4] which excludes agricultural workers and the military in the numerator and includes all people who are aged 16+ in the denominator, so as your population ages, the indicator would worsen.

[1] https://data.oecd.org/emp/employment-rate.htm

[2] https://data.oecd.org/emp/labour-force-participation-rate.ht...

[3] https://www.ons.gov.uk/employmentandlabourmarket/peopleinwor...

[4] https://www.investopedia.com/terms/c/civilian-labor-force.as...