Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year | Album | Song | Duration | Artist |
| --- | --- | --- | --- | --- |
| 2010 | TRAX Mini Album Volume Up | "Healing" |  | with TRAX |
| 2010 | Oh! | "Boys & Girls" |  | with Girls' Generation |
| 2010 | 1st Asia Tour "Into The New World" | "Barbie Girl" |  | Duet with Jessica |
| 2012 | History of Salary Man OST | "Bravo" | 03:12 | Duet with Leeteuk |
| 2012 | One Dream (Single) | "One Dream" | 02:29 | with BoA & Henry |
| 2012 | MAMA | "Two Moons" | 02:59 | with EXO |
| 2012 | Only One | "One Dream" | 02:29 | with BoA & Henry |
| 2014 | Toheart | "Delicious" |  | Duet with Woohyun from Infinite |
Question:
how many years were between the albums only one and toheart?
Answer:
2