Number of “vampire” movies from 1916-2011

I’m a big fan of True Blood, The Vampire Diaries and other vampire related shows and movies so I did a small exercise:

1. Get all movies categorized with “Vampire” from IMDB and sort by release date: http://www.imdb.com/keyword/vampire/?title_type=feature&sort=release_date
2. Copy paste all 758 titles to a spreadsheet
3. Import spreadsheet in Google Refine
4. Search for all dates and note down number of movies per year in a spreadsheet
5. Visualize spreadsheet using Google Docs

The image shows the absolute number of movies tagged with keyword “Vampire” from 1916-2011 with, interestingly enough, a few releases during World World II, a growth in the early seventies and a big peak in 2009. It would be great to normalize the data with the total number of movies released that year but I do not seem to be able to find that data in IMDB. For example: “Number of movies released in 2009.” If anyone has an idea on how to approach that, please feel free to leave suggestions in the comments :)

Please note that these are not necessarily all vampire movies but movies labelled with the keyword “vampire.” The small exercise served as a good recommendation filter as well because I found a Pedro Almodóvar movie I have not seen yet. Los Abrazos Rotos (2009) is not a movie about vampires but contains several references to vampires. Feel free to work with the spreadsheet, there might be more interesting things in there.

UPDATE
Thanks to Breyten (see comments) I was able to get the total number of movies per year in the IMDB to calculate the relative number of labelled vampire per year. The seventies are back! :)