The graph shows AMD and Intel market share which is based on thousands of PerformanceTest benchmark results and is updated daily. The chart only includes x86 processors and does not include other chip architectures these manufacturers may sell.
In Q1 2017 Intel’s market share according to the Passmark graph shows 81.90 percent total while AMD has 18 percent. A snapshot taken on July 2 however, shows the Intel share drop to 76 percent while AMD rose to 24 percent.
Passmarks does not really talk about shares and no doubt the Intel fanboy suicide squad will make a big thing about this. However it is an indication that AMD is making inroads into Intel's bottom line. In AMD's favour the figures only take into account chips installed in PCs so do not account for anything in a console.
As the PerformanceTest software only runs on Windows OS and counts on user submitting their benchmarks. This chart may be non reflective of the non Windows user base.