This is the timeline of Korean Boy Groups when they formed as a group...

1996 - H.O.T 
1997 - Sechs Kies 
1997 - TAESAJA
1997 - N.R.G 
1998 - SHINHWA

1998 - 1TYM
1999 - G.O.D
1999 - CLICK-B
2000 - UN
2001 - K-POP

2002 - AKDONG CLUB
2002 - BLACK BEAT
2003 - BUZZ
2003 - DONG BANG SHIN KI (DBSK)
2005 - SS501

2005 - SUPER JUNIOR
2006 - BIGBANG
2007 - FT.ISLAND
2008 - SHINEE
2008 - U-KISS

2008 - 2PM
2009 - MBLAQ
2009 - B2ST
2010 - CN.BLUE
2010 - ZE:A

2010 - INFINITE
2010 - TEENTOP
2011 - BLOCK.B
2011 - B1A4 
2011 - BOYFRIEND