Adoption contact

As adoptive parents to our locally adopted daughter, we consider ourselves quite lucky with regard to contact agreeement between us and our daughter's biological mother.  As part of the 'open' adoption arrangments made prior to an adoption order being legalised in court, contact can vary from as little as an annual update given to the birth parent/s to as much as 3-4 visitations each year.  When I say we consider ourselves lucky, our commitment to our daughter's biological mother is just an annual update, involving just a written letter telling of progress and anything we feel relevent to share, along with photos. 
When I look back at the time when we quite happily accepted the fact we may have to 'share' our daughter with her biological parent's, I can now say I am much happier with the fact we don't have that complication in our lives.  And now five years of updates on, I consider why should contact and or updates be limited to the adoptive parents having to provide the information.  I often wonder what my daughter's biological mother is doing with her life now, what she feels, what her likes and dislikes are; to me this is all comparative, because there will be a time my daughter will ask questions that I won't have answers for.  I believe that under the 'open' adoption arrangements in our country, the issue of updates from both parties should be put in place; after all adoptions are put in place with the best interests of the child put foremost.  This suggests to me that the adopted child should then be given as much information as what is expected to be given to the biological parent's.