Table 1: Method adopted in study.

Observational Studies
Year of the study	First study: September 1997 Second study: August 1999 Third study: June 2001 Forth study: April 2002 Fifth study: December 2005 Sixth study: September 2009 Seventh study: November 2013 Eighth study: December 2014 Last study: May 2017
Data collection	Based on Pre-tested protocol.
Observation points	Based on black spots in 5 regions in Lebanon: Mount Lebanon, Metropolitan area of Beirut, The North, The south and Bekaa.
Observation procedure	2 trained research assistants completed the protocol at each site.