Is there an increase in papers authored by undergraduates? I am an undergraduate student in STEM.

I have noticed that several of my peers (also in STEM) have published in journals or conferences (multiple times).
I have also seen that in online forums for graduate admissions (such as PhysicsGRE), almost all the profiles have published several times in conferences and journals (granted that profiles in online forums do not present a well-rounded view of undergraduate students).
Many of them are also first or second authors in their papers.

Has there really been an increase in papers co-authored by undergraduates? Does this mean that publishing a paper does not carry the same level of significance as it used to in graduate admissions?
I know I am being paranoid, but I am hoping to apply to graduate school and I feel under pressure to publish since it seems like there are so many who do this, and hence someone who has not published any of their research would not stand out to the admission committee. This pressure is at the back of my mind every time I am working on my research, and is preventing me from enjoying its process.
Of course, this could be confirmation bias and I tried to find statistical answers regarding this, but could not find any, so I am asking here, since several members here take part in the graduate admissions process.
Has there really been an increase in papers co-authored by undergraduates?

These facts can be established:

There has been an increase in the number of undergraduates, except for recently in a few areas that have falling birth rates.
There has been an increase in the number of papers published.
The average number of authors per paper has increased.
For most papers, it is impossible to tell if an undergraduate is an author without asking the authors.

On balance, I think that there has been an increase in papers authored or coauthored by undergraduates, but that it is impossible to tell how big that increase is because nobody is collecting the data.

This pressure is at the back of my mind every time I am working on my research, and is preventing me from enjoying its process.

As a PhD student in STEM, you will be assessed primarily on your research publications.  If you particularly dislike being assessed that way, do not get a PhD in STEM.

Does this mean that publishing a paper does not carry the same level of significance as it used to in graduate admissions?

The number of PhD students is also increasing and admissions practices are slow to change, so I doubt there has been or will be much change.