3.19.4   Applying  public  procurement  procedures   Studies  have  shown  that  Public  Procurement  in  Ghana        Utilizes  about  80%  of  national  tax  revenue    Represents  about  24%  of  total  imports    Represents   between   50   –   70%   of   national   budget   (   after   deduction   of   national   emolument)    Accounts  for  about  17%  of  Gross  Domestic  Product   It  has  also  been  noted  through  research  that  a  5%  saving  in  procurement  is  equivalent  to  a  20%   increase  in  sales  volume  in  relation  to  organizational  profit.     To   ensure   effective   implementation   of   the   Act   663,   the   Public   Procurement   Authority   has   initiated  a  process  of  monitoring  and  evaluation  by  developing  an  assessment  tool  termed  the   Public  Procurement  Mode  of  Excellence  (PPME)  software  which  allows  for  the  qualitative  and   quantitative  measurement  of  public  procurement  systems.  The  PPME  tool  is  an  evidence  based   instrument   which   uses   documentary   evidence   of   contract   details   collected   from   entities   as   inputs  to  generate  reports.     In  2005  PPA  conducted  the  assessment  of  100  entities  within  the  Greater  Accra  Region.  In  2006,   213   entities   were   assessed   and   in   2007   financial   year   515   entities   have   been   assessed.   The   sample  size  of  entities  assessed  included  entities  from;   • The  State  Owned  Enterprises   52