I'm doing a statistical exercise and I need to group all the numbers in groups of 2 (4 groups totaling 8 numbers) with all 8 labels following the exact same model so to speak. As you can see below, each of these numbers has to have the label with the same order number. For example: under 7.43 should be Knop, under 6.06 should be Knop+R and so on and so forth. However, as I've done it, the last 2 labels are used for every bar. Am I not doing this right and if so, what's the proper way to do it?
Here's the code: 
 
BarChart[{{7.43, 6.06}, {5.34, 12.43}, {6.1, 7.4}, {6.76, 6.56}}, 
 ChartLabels -> {{"Knop", "Knop+R"} , {"Knop-N", 
    "Knop-N+R" }, {"Knop-P", "Knop-P+R"}, {"Knop-K", "Knop-K+R"}},
  ChartElementFunction ->  "GlassRectangle", ChartStyle ->  "Pastel", 
 ImageSize -> 700, ChartLegends -> {"Knop", "Reglalg"}, 
 LabelStyle -> {14, Bold},
  PlotLabel -> "Lungimea rădăcinii principale tratate cu Reglalg", 
 AxesLabel -> {"", "cm"}] 
The results: 