scanf error에 관한 질문

7.4 다중 선택 강의를 따라 하다 C6031 Return value ignored: 'scanf' 를 해결하지 못하고 있는 상태 입니다.

일단 제가 만든 코드는 아래와 같습니다.

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

#define BASE1   12000000.0
#define BASE2   46000000.0
#define BASE3   88000000.0
#define BASE4 150000000.0
#define BASE5 300000000.0
#define BASE6 500000000.0

#define RATE1 (6.0 / 100.0)
#define RATE2 (15.0 / 100.0)
#define RATE3 (24.0 / 100.0)
#define RATE4 (35.0 / 100.0)
#define RATE5 (38.0 / 100.0)
#define RATE6 (40.0 /100.0)
#define RATE7 (42.0 /100.0)

#define BASIC_DEDUCTION 1500000.0

int main()
{
	double income = 0.0;
	double tax = 0.0;
	double tax_base = income - BASIC_DEDUCTION;

	printf("Enter your annual income : ");
	
	scanf("%f", &income);

	if (tax_base <= BASE1 && tax_base > 0)
		tax = tax_base * RATE1;
	else if (tax_base <= BASE2)
		tax = (BASE1 * RATE1) + ((tax_base - BASE1) * RATE2);
	else if (tax_base <= BASE3)
		tax = (BASE1 * RATE1) + ((BASE2 - BASE1) * RATE2) + ((tax_base - BASE2) * RATE3);
	else if (tax_base <= BASE4)
		tax = (BASE1 * RATE1) + ((BASE2 - BASE1) * RATE2) + ((BASE3 - BASE2) * RATE3) + ((tax_base - BASE3) * RATE4);
	else if (tax_base <= BASE5)
		tax = (BASE1 * RATE1) + ((BASE2 - BASE1) * RATE2) + ((BASE3 - BASE2) * RATE3) + ((BASE4 - BASE3) * RATE4) + ((tax_base - BASE4) * RATE5);
	else if (tax_base <= BASE6)
		tax = (BASE1 * RATE1) + ((BASE2 - BASE1) * RATE2) + ((BASE3 - BASE2) * RATE3) + ((BASE4 - BASE3) * RATE4) + ((BASE5 - BASE4) * RATE5) + ((tax_base - BASE5) * RATE6);
	else if (tax_base > BASE6)
		tax = (BASE1 * RATE1) + ((BASE2 - BASE1) * RATE2) + ((BASE3 - BASE2) * RATE3) + ((BASE4 - BASE3) * RATE4) + ((BASE5 - BASE4) * RATE5) + ((BASE6 - BASE5) * RATE6) + ((tax_base - BASE6) * RATE7);

	printf("Your tax amount for the annual income is %f.\n", tax);
	
	return 0;

}

계속 scanf에 입력한 값이  정확히 반영되지 않아 debug를 해보니 제가 입력한 값을 받아들이는게 아니라 scanf returned value 1 int 을 보아하니 제가 입력한 값의 갯수를 반영 하는듯 합니다.

조언 부탁드립니다.