The ratio of the current to base vs the current to the collector
For a collector current of 10 mA, the Electrical Characteristics state that the Hfe can be between 100 and 300 - you have about 190, so that seems fine to me.

In the last three lines of your table, the transistor is in or near saturation - the Emitter-collector voltage is very small, so the Hfe calculation is meaningless - the transistor can't possibly increase the collector current beyond about 8.3 mA.

Try the experiment again with a lower value collector resistor, or higher collector voltage, so you can get a higher collector current.