We spent a lot of effort to obtain all the data and keep the TIOBE index up to date. In order to compensate a bit for this, we ask a fee of 5,000 US$ for the complete data set. The data set runs from June 2001 till today. It started with 25 languages back in 2001, and now measures more than 150 languages once a month. The data are available in comma separated format. Please contact sales@tiobe.com for more information.