Refer coinmarketcap.com. The correction do occure every year. But the time is not known. Its normal with crypto currencies. If you look at the data, we had a huge correction in 2015 losting for more than 400 days loosing more than $5000. Correction always end with huge hike in price. The hike was more than 130 percentage compared to the loss occured in last 400 days plus. Currenct correction and the loss occured due to closing of tradings and exchanges.