According to OLR Report 2015-R-0111, very few proposed bills eventually become laws. The report examines bills introduced during regular session from 2009 to 2014. It does not include special sessions, which consider only emergency certified bills and may be convened at any other time.
A proposed bill is a bill introduced by an individual legislator at the beginning of a session, not fully drafted. There were 4,864 proposed bills introduced between 2009 and 2014. Of those bills, 208 (approximately 4%) were enacted into law. The total bills enacted into law across the six year period, was 1,590. Therefore, approximately 1% of the enacted bills were proposed bills. The total enacted bills include raised bills, public acts, and special acts passed by the General Assembly.
For more information, read the full report.