The other day in the car, C. asked me how much of my iPod was hip-hop. She thought that it must have been at least 70 or 80 percent, but I was sure that it was less, probably closer to 50 percent. She was adamant that it must be more, so I did the only thing possible (as a complete and total nerd) to resolve the issue. I decided to find out definitively what portion of my library fell into each musical genre.
The above graph illustrates the breakdown of my iTunes library, excluding the archives of my radio show. On the left is a stacked bar graph of the genres by number of songs, and on the right is a stacked bar graph by total file size. Total file size gives a rough estimate of the actual time for each genre, although it's not perfect due to the fact that not all the files in my collection are ripped at the same bit rate. There are about 60 or so genres in the graph, but that is because I have exerted a level of granularity over my collection that very few people do. For example, I have a House category, and House/Deep and House/Disco categories. I have tried to color genres that could be lumped together - Alternative & Punk, Pop, Rock, and a few other categories are all yellow; most electronic styles are gray, hip-hop related categories are red, etc.
As you can see, approximately 40% of my library is hip hop-related, and about 30-35% of my library is rock-related. Jazz accounts for about 8% of the total number of songs, but fully 12% of the archive's disk space. This is to be expected - jazz songs tend to be longer on average than other genres. Rock songs tend to be shorter.
That's all well and good, but it doesn't answer the original question - what percentage of my iPod is hip hop? I mean, I guess it's possible that I've disproportionately loaded it with hip hop, right? Well, it turns out that that is not the case.
It turns out that the distribution of songs on my iPod nearly mirrors that of the main library. If anything, it's actually heavier on the rock. Interestingly, electronic music takes up a fair bit of size on the iPod without making its presence felt in the number of songs - most of those are DJ sets, which are around an hour long each. There is definitely less jazz as well, which makes sense - I don't usually listen to jazz in the car.
Anyway, this is a gross misuse of my time and Excel, but I have definitively laid to rest the question. Only 40% of my music is hip hop. (Although I'm sure that will change dramatically if I ever get around to archiving all of my vinyl...)