Spearman's rank correlation.

It would be useful if you provided a scatterplot of the two variables as that would tell us a lot, even better with a boxplot on each axis.

https://rdrr.io/cran/car/man/scatterplot.html

Hi Aehsan Ahmad Dar ,

Spearman's and Kendall's correlation coefficients are usually suggested for non-normally distributed data. You might refer to these two articles.

Chok, N.S. (2010). Pearson's versus Spearman's and Kendall's correlation coefficients for continuous data University of Pittsburgh]. http://d-scholarship.pitt.edu/id/eprint/8056

de Winter, J.C., Gosling, S.D., & Potter, J. (2016, Sep). Comparing the Pearson and Spearman correlation coefficients across distributions and sample sizes: A tutorial using simulations and empirical data. Psychol. Methods, 21(3), 273-290. https://doi.org/10.1037/met0000079

Hope this could be helpful,

Duong,

Spearman correlation is suggested

For more reading

Article Comparing the Pearson and Spearman Correlation Coefficients ...