I am having trouble interpreting the output of plot(irf) in R. As an example:

```
data(Canada)
example = VAR(Canada)
irf = irf(example, n.ahead = 10, orthogonal = TRUE, cumulative = TRUE)
plot(irf)
```

Produces the following plot

My understanding of the plot is that it shows the expected change in the variables due to a one unit shock to e. However, shouldn't all the variables start from y = 0 if this is the case? Looking at the plot for U, it starts at a point above zero, which does not make much sense to me.

r