private int calcFitness(String target) {
		assert target != null;
		assert target.length() == data.length();
		
		int totalFitness = 0;
		
		for(int i = 0; i < target.length(); i++) {
			if(target.charAt(i) == data.charAt(i)) {
				totalFitness++;
			}
		}
		
		return totalFitness;
	}