I think there are two meaningful bits of data here: the tax burden on corporations, and what share of the overall tax burden is paid by corporations. The article's phraseology ("business contributes smallest share") invites the latter comparison. But the former tells an interesting story as well:
https://data.oecd.org/tax/tax-on-corporate-profits.htm#indic....
In Germany, France, Italy, and Spain, corporate taxes amount to 2-2.4% of GDP. The U.K. is at 2.8%, while the U.S. is at 1.9%.[1] Although the U.S. raises more of its taxes from corporations than Germany, France, Italy, or Spain, it has a much lower tax burden overall. However, the absolute tax burden on corporations is not that far off. Germany was at 1.7% in 2012, while the U.S. was at 2.3% in 2104.
Same thing for income taxes: https://data.oecd.org/tax/tax-on-personal-income.htm#indicat.... Income taxes ranged from 7.5% to 10.9% of GDP Germany, France, Italy, Spain, and the UK in 2017. The U.S. was at 10.5%, near the top of the range.
Almost all of our overall much lower tax burden is explained by the fact that our "middle class taxes" are far lower than in Europe. Socials security taxes are 6.3% of GDP, versus 11.5-16.8% in France, Germany, Italy, and Spain. (The U.K. is at 6.4%.) https://data.oecd.org/tax/social-security-contributions.htm#....
Consumption taxes in the U.S. are just 4.3% of GDP, versus 9.7-12% in the U.K., Spain, France, Germany, and Italy: https://data.oecd.org/tax/tax-on-goods-and-services.htm#indi....
What is the policy takeaway? Those on the left point to Europe and say "we should be more like that; those countries have already figured out how to have a fairer, more humane society." What would our taxes look like if we raised the U.S. tax burden to European levels, but also adopted a similar distribution of taxes? Corporate taxes would go up slightly. Income taxes would not go up at all. Middle class taxes would double or triple.
Put it another way. What if we raised income taxes to Swedish levels? We would add about $500 billion in revenue, assuming that did not reduce GDP. Nice, but not even enough to balance the budget. What if we raised consumption taxes to Swedish levels? We'd raise $1.55 trillion, enough to balance the budget, pay for free college, and make a serious dent in universal healthcare.
What if we tried to raise that same money through income taxes? Our income tax burden would shoot to 18.5% of GDP, higher than all but Denmark (which is a huge outlier in the OECD). And what if we tried to raise that money from just the top 1%, like the left wants to do, instead of from everybody, as in Sweden (where the top tax bracket kicks in at $70,000)? You'd have to raise taxes on that group to 100% of income.
[1] I use these countries as reference points because they are the largest in the EU28--accounting for over 70% of the population.