IDC quality control failed. Don't they use spreadsheets?
The biggest error looks like Lenovo Q416 should be 4357 (not 3592) if you go by last year's blurb. Jan 2017: www.idc.com/getdoc.jsp?containerId=prEMEA42255917 Jan 2018: www.idc.com/getdoc.jsp?containerId=prEMEA43518918
The table doesn't make any sense. It is as if they are making results up. Lenovo has an increase of 23.6% while HP 11.3%. And the sum over different sales in 2016 is also messed up.