The UK income tax system has a progressive tax rate that gets higher as your income is higher. However it has a few quirks. I've been meaning to graph the effective rates, and today I felt like learning a bit more R to do it. I've included income related student loan repayments and National Insurance because they are, to some extent, income-tax-like.
The code at https://github.com/benclifford/r-income-tax can generate the following three graphs:
Marginal income tax rates, coloured by component, for varying income:
Total tax, for varying income:
Fraction of income taken as tax, for varying income: