Electrolytic Caps- typical leakage current values.

[Nick]

Its often worth looking at manufacturers' technical bulletins for this sort of information - obviously, looking at current documentation reflect current technologies, not the stuff of old radios etc.

However, the following is a good read (if you like that sort of thing):
http://www.epcos.com/web/generator/Web/S...90592.html

BHS/EPOS/RIFA have a whole bunch of useful application notes & technical bulletins...