1) "Administrative Assistant" postings attract lots of job seekers. For some reason unemployed candidates like to apply for these jobs.
2) Scammers like to post "Administrative Assistant" postings too. I'd say that at least half of "Administrative Assistant" postings are scam (scammers are trying to recruit people for money laundering or pyramid scheme).
3) Job postings looking for software developers are totally different story. There are plenty of openings chasing limited pool of available developers.
4) See how jobs/resumes ratio varies for different skills: