WOW. The misinformation in this thread, or even better lack of information, is outstanding.
Do you even know what the 91dbB and 109dB values stand for?
It is the intensity of the exhaust sound of a vehicle which is
stationary, a vehicle which is
not moving. It is measured at 3750 RPM. And that's the 109dB value for MY18 and 91dB for MY19 respectively .
MY18:
MY19:
The
driving/road noise of the car, is
72dB for MY18 and
71dB for MY19.
And no, 1dB difference is very hard for the human ear to detect, even for professionals in the music business.
Also, the human audio memory is so incredibly short, that there's no way someone will even notice the difference between the two cars
while driving.
As of now there is zero evidence that supports that there is any difference between MY18 and MY19.
There is also a huge number or variables that make such comparisons futile. (fuel, air pressure, engine state, speed, RPM, human input/error, temperature, etc).
If yours doesn't correspond to the norm, then it has to do with your specific vehicle and not with a production year as a whole, and you should probably look into that.