<prompt> Translate the following text to EnglishTangu kuwa Msimamizi Mkuu, moja ya shughuli muhimu zaidi ambazo GAO imekuwa ikifanya ni maendeleo ya mpango wake wa kwanza wa kimkakati kwa karne ya 21.  <response>: Since I became Comptroller General, one of the most important activities in which GAO has been engaged is the development of its first strategic plan for the 21st century. 