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:
| Name | Style | Opened | Manufacturer | Themed Area |
| --- | --- | --- | --- | --- |
| The Shock Wave | Standing Up Rollercoaster | 1994.0 | Intamin | Action Park |
| G Force | Steel Sit Down | 2005.0 | Mauer Söhne | Action Park |
| Ben 10 – Ultimate Mission | Steel Sit Down | 2011.0 | Vekoma | Aerial Park |
| Buffalo Mountain Coaster | Steel Sit Down | 1987.0 | Zamperla | Aerial Park |
| Troublesome Trucks Runaway Coaster | Steel Sit Down | 2008.0 | Gerstlauer | Thomas Land |
Question:
Which average Opened has a Manufacturer of vekoma?
Answer:
2011.0