Google’s Google Trends service reports a metric they call “interest over time”. Trends offers a simple — but due to Google‘s scale quite robust — means for assessing the relative mind share of the search terms people use with the world’s most popular search engine.

Google likes to celebrate this capability around the end of each year; here’s its “Year in Search” page for 2024. Popular search-terms are a major source of interest for the media (here‘s ABC news), marketers and researchers.

Likewise, last year the PDF Association provided a review of how Google saw PDF in 2023. We've taken another look in 2024 to see what‘s changed. What follows is a series of screen-shots, as Google Trends does not (yet) facilitate sharing a snapshot of a given search (PDF would work well for that :-). These searches were conducted on December 13, 14 and 16, 2024.

NOTE: In all searches conducted for this article we used Google Trends’ “search term” option rather than the fuzzier “subject” or “file format” options. The results are relatively similar, in any event. The actual values Trends generates for a given report vary over time, so your own results may differ (somewhat) from mine.

Why look at searches for “pdf” at all?

Of course, 99.9% of people searching for “pdf” have no interest in the format itself. That said, there are not so many subjects for which “pdf” is likely to generate a significant volume of searches. Of course, some users will be looking for “pdf software”, or guidance on using pdf, and so-on, but at scale, it’s reasonable to infer that, for the most part, when a user includes “pdf” in a search they are seeking some sort of publication, form or other document they expect (or prefer) to find as a pdf file.

Peak PDF

One obvious question given Google‘s “interest over time” model for reporting relative search term popularity: when was “peak pdf” – the moment in time when worldwide interest in “pdf” was highest relative to all searches?

When we first looked back, in October 2018, peak pdf was in September, 2015.

When we checked again, in late October, 2022, peak pdf had just come in March of the same year.

On Monday, December 16, 2024 (see the screen-shot), peak pdf was in February 2024. Check it yourself.

Worldwide, although the increase in relative searches for pdf substantially flattened in 2014, an upward trajectory remained. Thereafter, Google noted “an improvement to our data collection system” in 2022 that resulted in a dramatic increase in pdf's “interest over time” metric; since then the term has continued to increase in relative popularity. In 2024, “pdf” is more popular, relative to all worldwide Google searches, than in any other year to date.

Make of it what you will, but PDF is going up. It’s actually quite difficult to find a word in the technology space that’s (a) been around as long as PDF and (b) isn’t going down (according to Google Trends). If you find one, please let me know!

Mind share (as expressed in search terms)

How does “pdf” compare to the most popular search terms Google’s search engine sees? A few weeks ago similarweb picked the top search terms for 2024 worldwide. When we add "pdf" it’s clearly in the game:

Geography

If relative interest in pdf continues to grow worldwide, where are searches for “pdf” increasing relative to all web-searches, and where are they not?

If we restrict Trends’ scope to the US, the overall trend is similar to the global trend, but a bit flatter, it’s also choppier; the low-points mostly correlate to summer and winter holiday periods:

Shifting the scale to the last five years to gain additional detail, it appears that, as of December 13, 2024, peak pdf in the US occurred in… November of 2024.

PDF’s relative popularity in Germany, however, has had a steadier rise. When it comes to searches for “pdf” Germany is much less seasonal as compared to the USA. Germany’s peak pdf… it’s more-or-less happening right now:

Prior to February, 2024 peak pdf in Germany (note the spike in the above image) came in June, 2018. Zooming into the month and country showed that Germans were searching for “wm spielplan pdf” (World Cup schedule pdf) and variations thereof. The actual peak pdf that month occurred on June 14, the day the World Cup opened… and I’ll say no more about it, to spare the feelings of my German friends. 🙂

“PDF” vs ??

So far as Google searches are concerned, few technologies show as much resilience as does PDF.

What other tech concepts or products compete with pdf for user’s searches? As noted above, Google and YouTube dominate Google searches worldwide. But both are falling relative to all searches, whereas pdf continues to rise.

“iPhone” remains a popular search, but, excepting the annual ritual in September, when new iPhones are announced, the proportion of searches for iPhone relative to pdf is down.

What about the really hot terms?

Given the popularity for pdf seen above, it's seriously impressive that the artificial intelligence terms have come so far so fast! ChatGPT did not even exist in Google Trends until the week of November 27, 2022!

If we zoom into California‘s Bay Area, which includes Silicon Valley, we find that chatgpt began to rival pdf in February 2023, and now, at the end of 2024 is approximately equal to pdf.

Conclusion

As noted above, in 2024, “pdf” was more popular, relative to all worldwide Google searches, than in any other of the last 20 years; Google Trends‘ entire history.

It's an extraordinary fact given the remarkable developments in web technology since 2004, not to mention the predictions at the time were that "internet publishing" would replace pdf pages. As the web has expanded in scope and context (especially with mobile devices), PDF‘s unique, unmatched utility as a general purpose final form digital document format keeps it going strong. After 20 years PDF is a complement, not a competitor, to web technology.

As PDF moves into its 4th decade we'll keep watching this trend.