The increase potency of exchange rate in bitcoin is clearly seen on this chart, which shows the change of exchange rate in the last months.
In January 2017 the price of one bitcoin was a little bit above $1.000, but at the end of that year it was above $18.000. But how high can the price go up? Wences Casares, member of the managing board of PayPal expects one Bitcoin will worth $1 million in 5-10 years.
Behind the outstanding increase of the price on the long run is the supply and demand. This is the reason why bitcoin is used today by average people in masses, since they recognized its fundamental advantages. This can be seen clearly in daily transaction numbers and the rising of its market value (market capitalization). Besides that - because of the preprogrammed algorithm - the supply is decreasing continuously. Both of these factors result in the increase of the price.