Tens of thousands of Indians have come forward over the past four months to declare a collective $9.5 billion in income that was never reported or taxed, India's finance minister Arun Jaitley announced Saturday. Jaitley said that number could increase because some declarations are still being processed. Under a government plan announced by Jaitley earlier this year, the 64,275 Indians who declared so-called black money during the four month period that ended Friday would pay 45 percent in taxes to the state but avoid criminal prosecution. Prime Minister Narendra Modi, who vowed to curb tax avoidance when he was elected in 2014, congratulated both Jaitley and those who chose to declare their black money Saturday. "I compliment all those who chose to be tax compliant in IDS-2016. This is a great contribution towards transparency & growth of the economy," he tweeted from his official account. This is not the first time the government of India has instituted such a tax amnesty program — Jaitley said a program in 1997 brought in $1.5 billion to the government. The government faced opposition to the action since the release of the so-called Panama Papers in April, which listed individuals and companies that had avoided taxes by setting up shell companies in Panama. About 500 Indians were among those accused.