Hi,
I have a time series like this:

1995, -.05
1996, -2.1
1997, 3.6
1998, 4.3
1999, -0.7
2000, -0.08

and I would like to sum just the positive and negative value separately
in this way

1995, -2.15
1997, 7.9
1999, -0.78

And I don't know if it is possible, thanks in advance.