How much of the English lexis comes from each of its influences?

Wikipedia has the following pie chart showing the word origins:

It shows the breakdown as

• Latin (including words used only in scientific / medical / legal contexts) ≈ 29%
• French ≈ 29%
• Germanic ≈ 26%
• Greek ≈ 6%
• Others ≈ 10%

It cites some references which back up these numbers but I don't have access to those.

To answer your question, it does not appear to be true that 50% of words are Germanic. However, that probably depends on what your context is. If you exclude scientific, medical, and legal, you will probably find a much lower incidence of Latin words. Given that English is itself a Germanic language, it's more surprising that Germanic doesn't account for MORE of the vocabulary.