Moreover, in all nations this problem has made it difficult for the industry to develop any type of reliable or credible tourism information base in order to estimate the contribution it makes to regional, national and global economics.

此外，在所有国家，这个问题都使该行业难以开发任何类型的可靠或可信的旅游信息库，以估计其对区域、国家和全球经济的贡献。