Predictions are hard. Especially the ones about the future. Here is an interesting infographic with some nice compression data, trends, technology penetration curves ... Spoiler: with current trends, we will have to wait until 2040 for number of 3d printers to match the number of persons in US.
Source and higher resolution image:
http://imgur.com/Mz5cmQh
Source and higher resolution image:
http://imgur.com/Mz5cmQh