Firstly, that's job postings -- not true employment numbers. The trend direction is probably aligned, but the degree of change might not line up as closely.

Secondly, is the new marketing person at my employer really a marketing person? He uses many of the same tools as do I (a software dev). Sure, what he produces is different from what I produce, but we both are able to manipulate data to make it do what we need it to do.

A job posting for his role very well might not be interpreted as anything even remotely being software development-related.