Finding number of independent samples using autocorrelation

I have a pressure signal (y) with 512000 samples and with a sampling frequency 5000 sample/sec. I am trying to find the number of statistically independent samples using autocorrelation. I used

autocorr(y)

I do not know if this is correct or how to get the number of independent samples. It will be very helpful to know how to get number of samples from Lag if that's possible

Answer 1

[Abhishek Ballaney]

https://in.mathworks.com/help/econ/autocorr.html