A fellow blogger was so bold as to proclaim that light novels are some of the most common sources of anime adaptations today. That got me thinking, is that really true? My husband didn’t think so. And so a new research post was born. (While researching this I found another post claiming almost every anime is adapted from manga. I’ll disprove that along the way.)
First of all, let’s look at anime from 2016 and this year. The aforementioned claim is from October 2016, which nests nicely in the middle of my interval. Regarding my methodology: I’m researching only nonH TV series (no OVAs or movies) that started that season (no continuing anime, like One Piece, but I count second seasons that started after a pause).
In total I have 393 anime series. 104 of those were not adaptations, also known as originals. In percentages, 26.5% of TV series were originals and 73.5% were adaptations. To disprove the parenthesized claim about almost every anime being a manga adaptation — 160 of 393 series were manga adaptations, which rounds to 40.7%. It is a high percentage, but nowhere near “almost every anime.”
Below I put together a graph of the adaptations, so my results excluding originals. The total is 289. As you can see manga takes up more than a half of the pie (55.4%) — this includes regular manga, yonkoma and webmanga. Orange light novels come to 13.1%. It would be the second highest percentage, if I didn’t add the two green slices – games and visual novels – together, totaling 50 series and 17.3 percent. I must concede that in either situation light novels are “some of the most common sources of anime adaptations.” Still, they do not make up a large part at all. In addition, a great number (19 out of 38) of those light novel adaptations come from 2017, that is after the claim was written.

Anime Adaptations 2016-7
To complete the circle, regular novels make up 6.6% of anime adaptations and the rest is anything that didn’t fit into my categories. For example anime adapted from pachinko machine commercials or illustration books (I’m talking about Honobono log).
That’s settled. My curiosity has been quenched, but another question arose – was it always like that? I think it’s pretty (about 100%) likely that it wasn’t. I’ll try to delve into that some other day. So look forward to that!