[NTG-context] "page i/n" in footer

Dear List, Does anyone know how to set the footer to be "page i/n" where i=current page number, n=total number of page? I've tried \setuppagenumbering[location=footer, command=\groupedcommand{page }{/\lastcounter[userpage]}] but \lastcounter[userpage] results in empty string. Thanks in advance. Best, Sylvain