The lackluster winter has ended, and it’s finally spring in the virtual currency world.

Bitcoin bulldozed its way past the $680 mark on Monday, hitting a high $689.87 with 15.65 million bitcoins in circulation—its highest since September 2014, when the cryptocurrency went on a free fall from more than $1,000 per single bitcoin.

Chinese investors, who are worried their country’s economy will result in the depreciation of the yuan, are still the number one factor behind the unrelenting surge in the price of bitcoin. The increased investment among Chinese traders are believed to account for about 95 percent of the current bitcoin trading volume, according to CoinDesk.

Another reason behind the spike: the scheduled shrink in supply of the digital currency.