dd manual page is very limited on this:
status=LEVEL The LEVEL of information to print to stderr; 'none' suppresses everything but error messages, 'noxfer' suppresses the final transfer statistics, 'progress' shows periodic transfer statistics
This does not say anything about the actual output, which looks something like this when I copy a large image file, e.g.:
dd if=input.img of=output.img status=progress
The transfer speed and the copying time so far is obvious, but what do the first three numbers mean?