Clearly, the ticklabels you wrote are (1:5000)/20. The first label is 0.05 --> 1/20, the second 0.10 --> 2/20, etc., etc., ...
Matlab did precisely what you asked it to... :)
The problem is the tick marks aren't every x value else't there would be 5,090 of them...you must label only the ticks; per the documentation tick labels are just a 1:1 mapping of the input ticklabel values to the tick locations; if there are more labels than ticks the rest are ignored; fewer and the array is used from the beginning as many times as needed. Since your axis has 10 intervals there are 11 ticks and you labeled them with the values [1:11]/20
instead to label the actual ticks at 1/20th tick value