Assessing the proportional hazard (PH) / proportionality assumption of a cox regression model

Dear all

I have fitted a cox proportional hazard regression model (coxphit) for some data. I would like to assess the proportional hazard / proportionality of that model and data in matlab. I have plotted the scaled schroedinger residuals from the stats section against the time variable.

stats = 
       covb: 0.0502
       beta: -0.7739
         se: 0.2240
          z: -3.4555
          p: 5.4926e-04
      csres: [237×1 double]
     devres: [237×1 double]
    martres: [237×1 double]
     schres: [237×1 double]
    sschres: [237×1 double]
     scores: [237×1 double]
    sscores: [237×1 double]

I struggle with the interpretation of that data and figure.

Any help on how to proceed would be appreciated.

Thank you