Write a question about the following article: The highest rate of provincial corporate income tax was reduced from 17% to 14% on July 1, 2006. It was further reduced to 13% on July 1, 2007, and finally to 12% on July 1, 2008. The tax on paid-up capital was reduced from 0.6% to 0.3% on July 1, 2006, to 0.15% on July 1, 2007, and abolished altogether on July 1, 2008. These displayed values were obtained by adding the corporate income tax for each year with the corporate capital tax.

Question about the article:
By how many percentage points was the provincial corporate income tax reduced between July 1, 2006 and July 1, 2008?