Aaron got Pure's numbers wrong
Gartner's method of determining market share data includes product revenue only. The numbers included for Pure are product + service revenue. The actual numbers that should have been included are lower and only would have extended XtremIO's lead.
Furthermore, you must adjust for Pure's fiscal year. For example Pure's Q4 is November/December/January, which means that for market share purposes you'd actually have to estimate their numbers lower to replace January with September (and so on for each quarter).
From Pure's own earnings presentations, their product revenue was (for their fiscal quarters):
Q1'15 (calendar year 2014): $22.1M
Q2'15 (calendar year 2014): $31.1M
Q3'15 (calendar year 2014): $43.8M
Q4'15 (calendar year 2014): $57.8M
Q1'16 (calendar year 2015): $63.6M
Q2'16 (calendar year 2015): $71.2M
Q3'16 (calendar year 2015): $113.6M
Q4'16 (calendar year 2015): $127.3M
Chris - would love to see you adjust your charts accordingly.