I have this matrix:

A =

1 1000
2 1010
3 1020
4 1030
5 1040
6 1050
7 1060
8 1070
9 1080
10 1090

If the first column is the variable X and the second column is the variable
Y I would like to see how correlated the data is. Computing the covariance
matrix gives:


C =

9.1667 91.6667
91.6667 916.6667

I have read that if an element in C is 0 there is no covariance between the
corresponding variables, if its positive there is a covariance between the
two variables and if its negative there is a covariance between X and -Y.

In C the covariance between X and Y is 91.6667. But how should that number
be interpretated and does the magnitude have anything to say?

If I plot the above data X and Y does not seem very correlated (close to
each other).