When loading Disk throughput sensors system monitor display in legend 'Accesses' instead of 'Data' and 'Data' instead of 'Accesses' for Read and Write. Total Accesses displays as it should.

Reproducible: Always

Steps to Reproduce:
1.Go to file > New tab
2.In sensor browser select disk throughput and sda
3.Load either Read or Write Data or Accesses as Line Graph

Actual Results:  
If Accesses was selected then the legend displays Data (but the monitor actually shows accesses) ; If Data was selected the legend displays Accesses (but the monitor actually show Data)

Expected Results:  
Display the right thing in the legend