what is the total amount of games activision developed?
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col : year | title | system | developer | publisher row 1 : 1984 | ghostbusters | atari 800, commodore 64, msx, zx | activision | activision row 2 : 1985 | ghostbusters | atari 2600, apple ii | activision | activision row 3 : 1987 | the real ghostbusters | arcade | data east | data east row 4 : 1987 | ghostbusters | sega master system | activision | sega row 5 : 1988 | ghostbusters | nes | bits laboratory | activision/tokuma shoten row 6 : 1989 | the real ghostbusters | commodore 64, amiga, zx spectrum, amstra | data east | activision row 7 : 1989 | ghostbusters ii | atari 2600, amiga, commodore 64, ms | activision | activision row 8 : 1990 | ghostbusters ii | nes | kemco | activision row 9 : 1990 | ghostbusters | sega mega drive/genesis | sega | sega row 10 : 1990 | new ghostbusters 2 | game boy, nes | hal laboratory | activision row 11 : 1993 | the real ghostbusters | game boy | kemco | activision row 12 : 2009 | ghostbusters: the video game | playstation 3, playstation 2, playstation portable, xbox 360, nintendo ds, wi | terminal reality, red fly studios, zen studios | atari,\nsony computer entertainment (europe only, ps row 13 : 2011 | ghostbusters: sanctum of slime | playstation network, xbox live, pc | behaviour interactive | atari row 14 : 2012 | ghostbusters: paranormal blast | android, ios | xmg studio |  row 15 : 2013 | ghostbusters | ios | beeline interactive | capcom
what is the total amount of games activision developed?
Year Title System Developer Publisher
1984 Ghostbusters Atari 800, Commodore 64, MSX, ZX Spectrum, Amstrad CPC Activision Activision
1985 Ghostbusters Atari 2600, Apple II Activision Activision
1987 The Real Ghostbusters Arcade Data East Data East
1987 Ghostbusters Sega Master System Activision Sega
1988 Ghostbusters NES Bits Laboratory Activision/Tokuma Shoten
1989 The Real Ghostbusters Commodore 64, Amiga, ZX Spectrum, Amstrad CPC, Atari ST Data East Activision
1989 Ghostbusters II Atari 2600, Amiga, Commodore 64, MSX, PC, ZX Spectrum, Amstrad CPC Activision Activision
1990 Ghostbusters II NES Kemco Activision
1990 Ghostbusters Sega Mega Drive/Genesis Sega Sega
1990 New Ghostbusters 2 Game Boy, NES Hal Laboratory Activision
1993 The Real Ghostbusters Game Boy Kemco Activision
2009 Ghostbusters: The Video Game PlayStation 3, PlayStation 2, PlayStation Portable, Xbox 360, Nintendo DS, Wii, PC Terminal Reality, Red Fly Studios, Zen Studios Atari,\nSony Computer Entertainment (Europe only, PS2 and PS3 versions)
2011 Ghostbusters: Sanctum of Slime PlayStation Network, Xbox Live, PC Behaviour Interactive Atari
2012 Ghostbusters: Paranormal Blast Android, iOS XMG Studio
2013 Ghostbusters iOS Beeline Interactive Capcom
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