Practical maximum number of graph elements

[Andy]

Hi,

I have a progress graph which adds two vertical bar elements and one
horizontal line data point each day. After almost a year it has
roughly 1000 elements that it needs to plot. This doesn't strike me as
a tremendous number of elements but as it has grown it has reached the
point where when that page loads it now takes almost a minute for my
javascript menu to work again.

Does anyone have any thoughts on whether this is just too many
elements to stuff into the graph. Or am I doing something else wrong?
Users of the site are assuming that it has crashed since they can't
click on the menu and are starting to complain. I'm probably going to
have to start thinning the graph out (by deleting every second data
element) but that would be disappointing because it finally has enough
data to look good :)