Thread: Population class

I have made a class that gets the starting population, the percent increase daily and the number of days the organisms will be multiplied.

public class popul
{
	//Creakte private fields
	private double pop_organism;
	private int percentIncrease;
	private int days_multiply;
	private double new_population=0;
 
 
	//Make a contructor
	public popul()
	{
		pop_organism=0;
		percentIncrease=0;
		days_multiply=1;
	}
	//take in a argument
	public void get_popPercent_daysMult(double population,int percent,int days_mult)
	{
		pop_organism=population;
		percentIncrease=percent;
		days_multiply=days_mult;
	}
 
	public void calculate_increase()
	{
 
		for(int counter=1;counter<=days_multiply;counter++)
		{
			pop_organism=(pop_organism*(percentIncrease/100))+pop_organism;
			System.out.print("Day"+ " "+counter+ " : "+pop_organism);
 
		}
	}
}]

My problem seems to lie in the public void calculate_increase method. For some aparents reason I'm getting

day 1 : 4.0 day 2: 4.0 day 3: 4.0 day 4: 4.0 day 5: 4.0

I have been working on this for one hour but just can't seem to figure it out! Thanks guys in advance oh and my sample input I'm using is

pop_organism=4;
percentIncrease=20;
days_multiply=5;