Controversial Windows 7 market growth or decline?

The latest report from NetMarketShare in June 2017 indicated that nearly all operating systems had a market share drop, with the exception of ... Windows XP increased to 6.94%.
Specifically, NetMarketShare data show that Windows 7 professional product key has decreased 0.42% market share, corresponding to a decrease of 0.01% over the same period last year. Meanwhile, Windows 8.1 product key was down 0.34% from the previous month.
NetMarketShare also recorded 91.51% of users using Windows, while Mac and Linux accounted for 6.12% and 2.36%, respectively.
On the other hand, data from StatCounter research shows that Windows' market share has risen to 84.31 percent, compared with 83.93 percent in the previous month. Meanwhile, market share for OS X, Linux and Chrome OS was 11.61%, 1.74% and 0.56%, respectively.
Based on simple calculations, it can be seen that Windows 7 has dropped to 38.55%, while Windows 10 product key has grown to a market share of 30.87%. At the same time, market share of Windows 8/ 8.1 and XP accounted for 9.94% and 4.10%, respectively.
The difference in NetMarketShare and StatCounter reporting comes from partner sites and their tracking code. In general, it does not fully describe the actual usage situation.