Yet more demographics (or "why manufacturing industry?")

I've collected the CIA data on composition of labour force by employment sector (agriculture / industry / services), composition of GDP ditto, total GDP and total labour force, and by means of two multiplications and a division produced a table, per country, of GDP per person employed in each sector.

Thirteen countries: the big five nearly-developed nations (Brazil, Russia, India, Indonesia, China), Peru because it had an incredibly small agricultural sector, Serbia because it had a very large industrial sector, Uganda as a developing nation, Thailand because we were talking about it on James Nicoll's LJ, the UK because I live there, the US and Canada because lots of people reading this live there, et la France, car c'est la France. Figures in thousands of US dollars per year at official exchange rate

Country	GDP per agriculturalist	GDP per industry worker	GDP per service worker
Brazil	5.6	33.6	16.6
Canada	82.9	124.0	73.1
China	1.4	10.6	6.8
France	53.9	86.0	110.7
India	0.7	5.5	4.3
Indonesia	1.6	11.8	4.4
Peru *	151.9 8.3	11.1 13.3	11.6 13.1
Russia	10.2	30.4	20.5
Serbia	6.9	8.9	44.7
Thailand	2	16.1	8.4
Uganda	0.3	4.9	4.1
UK	79.5	113.9	79.3
USA	184.8	78.5	95.8

* I believe the Peruvian National Statistics Office more than I do the CIA

Spreadsheet here.

I'm not sure I believe these answers, which means I suppose that I don't believe some of the input numbers. Western farmers are incredibly productive, yes; industry is almost always more productive per worker than the service sector, yes; but the Serbian service sector three times as efficient as the Brazilian?