Relationship between dynamic range and number of samples
Theoretically if you take two identical signals and average (in the presence of benign noise) you get a 3 dB increase in signal to noise ratio. Consider two identical signals with different background noises having same RMS noise amplitudes...

When you add the two waveforms (signal and noise), the signal doubles because they are the same individually (6 dB increase) but the total noise only goes up by 3 dB because the individual noise sources are not coherent. Hence SNR rises by 3 dB. Take 4 samples and you get a 6 dB improvement. Take 16 samples and you get a 12 dB improvement.

Take 64 samples and you get an 18 dB improvement. So, with 100x oversampling you'll get something like a 20 dB improvement.