This week was a big one for those advocating against a tampon tax.

First, on Thursday, California took the next step in the legislative push to end the state's tax on feminine hygiene products. The state senate backed legislation in a 38-0 vote that would repeal the state's sales tax on tampons and all other feminine hygiene products.

Then, on Friday, the Republican governor of Illinois signed a law repealing the tampon tax in that state entirely.

The change will take effect in Illinois Jan. 1, 2017.

In California, the bill is headed back to the state assembly, which has to approve changes made in the senate. The proposal was already approved there, so it's looking like California will join Illinois and the few other states that no longer impose these taxes.

Most U.S. states do tax tampons since they aren't considered a "necessity," like food or medicine, exempt from sales tax. Only a few states including Maryland, Massachusetts, Pennsylvania, Minnesota and New Jersey don't tax feminine hygiene products. New York abolished its tampon tax in July.

Canada officially stopped charging its tampon tax July 1. Activists in Spain, the UK and other countries have pushed governments to stop imposing an effectively gender-based tax on an essential good.

In California, the sales tax applied to tampons is 7.5 percent. That leads to California women paying more than $20 million every year in taxes on basic sanitary products.

“Fundamentally this is about gender equity and leveling the field,” California State Assemblywomen Cristina Garcia, who introduced the bill, said in a statement. “Every month, for 40 years of our lives, we are taxed for being born women. Every month of our adult life we are taxed for our biology. Every month we are told our periods are a luxury, while also being told they are something to be ashamed of and [that] we must hide. Let me be clear, on biology, periods are not luxuries and they are definitely not something women should be ashamed of, period."