Does 80% of government data really contain a locational component?

If you've read any amount of the GIS literature, you've no doubt come across the assertion that:
"80% of government data contains a locational, or geospatial component..." or, some words to that effect.

Have you ever stopped to wonder where this assertion comes from? Have you ever seen a citation for it? I haven't. How many of the results of this query cite the original source? (Exactly none, in case you were wondering.) Furthermore, how was the 80% figure arrived at? And, what is the origin for this assertion? I have always thought that the assertion came from the 1987 report, from Lord Chorley & co., Handling Geographic Information, but I'm not certain.

I should add that I suspect that most government data does indeed contain some locational component, - a place name, an address, the name of a landmark, or even geographic coordinates. So, I it's completely plausible to me. But, why do we as a community continue to repeat the assertion, taking it at face value? We take it as an act of faith really, don't we? Seems plausible, after all.

Here's the citation for the Chorley report, if anyone is able to get a copy and verify:
Handling of Geographic Information. Report to the Secretary of State for the Environment of the Committee of Enquiry into the Handling of Geographic Information. Chairman: Lord Chorley. London: HMSO, 1987. ISBN 0 11 752015 2