The following table shows a sample of historical total returns of shares in two different companies A and B.
| Stock Returns | ||
| Total effective annual returns | ||
| Year | ##r_A## | ##r_B## |
| 2007 | 0.2 | 0.4 |
| 2008 | 0.04 | -0.2 |
| 2009 | -0.1 | -0.3 |
| 2010 | 0.18 | 0.5 |
What is the historical sample covariance (##\hat{\sigma}_{A,B}##) and correlation (##\rho_{A,B}##) of stock A and B's total effective annual returns?