Why steem value suddenly crossed 5 $

I was not checking the steem value for past one week. I thought it might reach 3.5$ by first week of 2018. But I got shocked when i see the price as 7.2$

As per coinmarket web site now it is

1 steem = 6.90$ on 04-jan-2018

I don't the reason for this sudden growth.please share if you read somewhere..

Also not sure this growth is going to be consistent.

But bitcoin price still shows as less than 16000$

ETH ethereum shows a consistent growth and reached 994.00$.its not a rapid growth, but i can see it as a gradual progress.