Spotfire calculate number of days since 'criteria in another column' -

i have [date] column , [status] column. [status] can either "up" or "down". want count number of days [status]="down"

date          status     new_calculated_column 1/1/2001              0 1/2/2001      down       1 1/3/2001              0 

any suggestions?

this work using sum or count

sum(if([status] = "down",1,0)) 

or....

count(if([status] = "down",1,0))