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:
| Title | Alternate Title(s) | Year | Manufacturer | Genre(s) | Max. Players |
| --- | --- | --- | --- | --- | --- |
| Ocean Hunter, The | — | 1998 | Sega | Shooting gallery | 2 |
| Off Road Challenge | — | 1997 | Midway | Racing | 1 |
| Off Road Thunder | — | 2000 | Midway | Racing | 1 |
| Off The Wall | — | 1991 | Atari Games | Breakout | 2 |
| Oh My God! | — | 1993 | Atlus | Puzzle | 2 |
| Oishii Puzzle Wa Irimasen Ka | — | 1993 | Sunsoft | Puzzle | 2 |
| Oli-Boo-Chu | — | 1982 | Irem |  | 2 |
| Ollie King | — | 2004 | Smilebit |  |  |
| Omega Fighter | — | 1989 | UPL | Scrolling shooter | 2 |
| Omega Race | — | 1982 | Midway | Multidirectional shooter | 1 |
| One Shot One Kill | — |  | Playmark | Shooting gallery | 2 |
| Onna Sansirou - Typhoon Gal | — | 1985 | Taito |  | 2 |
| Operation Thunderbolt | — | 1988 | Taito | Shooting gallery | 2 |
| Operation Tiger | — | 1998 | Taito | Shooting gallery | 2 |
| Operation Wolf | — | 1987 | Taito | Shooting gallery | 2 |
| Operation Wolf 3 | — | 1994 | Taito | Shooting gallery | 2 |
| Orbit | — | 1978 | Atari | Multi-directional shooter | 2 |
| Ordyne | — | 1988 | Namco | Scrolling shooter | 2 |
| Oriental Legend | — | 1997 | International Game System | Beat 'em up | 4 |
| Osman | Cannon Dancer | 1996 | Mitchell Corporation | Platformer | 1 |
| Otomedius | — | 2007 | Konami | Scrolling shooter |  |
| Outfoxies, The | — | 1995 | Namco | Shoot'em up/\nFighting game | 2 |
| Outlaw | — | 1976 | Atari | Shooter | 1 |
| OutRun | — | 1986 | Sega AM2 | Racing | 1 |
| Out Zone | — | 1990 | Toaplan | Scrolling shooter | 2 |
| OutRun 2 | — | 2003 | Sega AM2 | Racing | 1 |
| OutRunners | — | 1993 | Sega AM1 | Racing | 2 |
| Outtrigger | — | 1999 | Sega AM2 | First Person Shooter |  |
| Over Drive | — | 1990 | Konami | Racing | 1 |
| Over Rev | — | 1997 | Jaleco | Racing | 2 |
| Over Top | — | 1996 | Alpha Denshi | Racing | 2 |
| Ozma Wars | — | 1978 | SNK | Fixed shooter | 2 |
Question:
how long has atari been manufacturing the the game off the wall?
Answer:
23 years