the formula for this would be starting population x (1- rate)^time
starting population is 600,000
rate is 2% which = 0.02 as a decimal
time is 2000 - 1970 = 30 years
put those into the formula to get:
600,000 x (1-0.02)^30
and now calculate it:
600,000 x (0.98)^30 = 327,290.59 round to 327,291 people