Suppose i have 50 pairs that are independent X,Y. The observations are paired. I have the following estimator for the correlation coefficient.

$\displaystyle r = \frac{\sum ^n _{i=1}(X_i - \bar{X})(Y_i - \bar{Y})}{\sqrt{\sum ^n _{i=1}(X_i - \bar{X})^2} \sqrt{\sum ^n _{i=1}(Y_i - \bar{Y})^2}}.$

How can I estimate the distribution of this estimator without knowing anything about the bivariate distriubution?