I'm not sure the nation wide raw statistics are that reliable in the field of software engineering without interpretation.
In the 90s tons of people who were de facto software engineers were listed as "Information Technology Workers". I suspect a lot of that still hasn't been shaken out of the system.
According to the BLS in the year 2000 there were 3.4 million information technology workers.
BLS had some classification changes over the years. I think it's interesting in the "this is how people thought about the role over the decades."
Today there are computer programmers (15-1251), and software developers (15-1252), and web developers (15-1254).
In 2018, there was a reclassification - https://www.dol.gov/sites/dolgov/files/ETA/oflc/Presentation... where 15-1132, Software Developers, Applications and 15-1133, Software Developers, Systems Software where reclassified into the software developers (15-1252) group.
The other thing that confuses this is that a lot of positions were classified as Computer systems analysts because that's a position that a TN visa can be hired for (there is no software engineer in there... and it wasn't until relatively recently that one could be a "software engineer" in Canada without being an Engineer.
Back in 2010 ... https://www.bls.gov/cps/cenocc2010.htm
Where the "Computer programmer" was the more junior classification and Software developers working on a word processor were classified differently than a software developer working on the operating system... and they were the more senior positions.This division still shows up in the definitions.
https://www.onetonline.org/link/summary/15-1252.00
https://www.onetonline.org/link/summary/15-1251.00