A $0.09 hike in the price of a single bus fare in Sao Paulo ignited the biggest protests to hit Brazil in over 20 years. As we noted earlier today, the bus fare hike was merely the last straw in a long list of public grievances about the shaky Brazilian economy.

But it’s worth noting that Sao Paulo’s bus riders are being majorly squeezed by fares. A fare price that sounds pretty minuscule in dollar terms actually takes up a huge chunk of Brazilian incomes for those at the bottom (and presumably, those who most need to use the bus).

The $0.09 hike brought the price of a single bus fare in Sao Paulo up to $1.47. Assuming Brazil’s city dwellers ride the bus twice daily—to and from work during the week, and to and from anywhere during the weekend—that’s $82.46 a month. For Brazilians making the minimum wage of $312.33 a month, that’s a whopping 26% of their income.

In Brazil’s lopsided economy, public funds are propping up a public transportation system that the public can’t afford.