Cost per base decrease over the last few years

[NGSsequencer]

Working on a case study for B-School. Since price for most testing has decreased at certain output levels, I was hoping the community might be able to provide me with some historical context

For providers who have had a hiseq for the last few years, probably added one or a few. How much has your cost per base decreased since the first runs of the HiSeq?

Also, If you bought the machine in 2011 what did you pay?
Thanks in advance for any feedback!

[jparsons]

The NIH has a lovely cost per genome graph, if you weren't already aware of it

http://www.genome.gov/sequencingcosts/

You can of course convert from per genome to per base if you so desire.