Each total income is subject to a tax, which is shown in the official tables issued by the Federal Office for 2018 and beyond. The ratio is based on the fact that it is mandatory to pay at least 10% of the total earnings to the federal tax, so that there is no risk of a surcharge.
Most of them paid the income tax advance, so it won’t be a problem. To put it simply, everyone who paid more than 10% in advance can expect a refund. Those who paid less than 10% in advance can expect to pay additional tax. State tax refunds are still possible – these processes individual states manage themselves and it always depends on the conditions of the state where you paid your taxes.