To solve this, we need to calculate the amount Sandy saved last year and this year, and then find the percentage of this year's savings relative to last year's.

Let's denote Sandy's base salary last year as S.

**Last Year:**
- Base salary: S
- Bonus: 3% of S = 0.03S
- Total income: S + 0.03S = 1.03S
- Income tax on salary: 15% of S = 0.15S
- Income tax on bonus: 20% of 0.03S = 0.006S
- Total income tax: 0.15S + 0.006S = 0.156S
- Income after tax: 1.03S - 0.156S = 0.874S
- Investment in mutual fund: 5% of 1.03S = 0.0515S
- Income after investment: 0.874S - 0.0515S = 0.8225S
- Mutual fund return: (4% for the first half and 6% for the second half on 0.0515S) = 0.0515S * (0.04 + 0.06) / 2 = 0.0515S * 0.05 = 0.002575S
- Income after mutual fund return: 0.8225S + 0.002575S = 0.825075S
- Savings: 10% of 0.825075S = 0.0825075S

**This Year:**
- Base salary increase: 10% of S = 0.1S
- New base salary: S + 0.1S = 1.1S
- Bonus: 7% of 1.1S = 0.077S
- Total income: 1.1S + 0.077S = 1.177S
- Income tax on salary: 17% of 1.1S = 0.187S
- Income tax on bonus: 22% of 0.077S = 0.01694S
- Total income tax: 0.187S + 0.01694S = 0.20394S
- Income after tax: 1.177S - 0.20394S = 0.97306S
- Investment in mutual funds: 4% of 1.177S = 0.04708S and 6% of 1.177S = 0.07062S
- Total investment: 0.04708S + 0.07062S = 0.1177S
- Income after investment: 0.97306S - 0.1177S = 0.85536S
- Mutual fund returns: 0.04708S * 0.07 + 0.07062S * 0.05 = 0.0032956S + 0.003531S = 0.0068266S
- Income after mutual fund returns: 0.85536S + 0.0068266S = 0.8621866S
- Savings: 15% of 0.8621866S = 0.129328S

**Percentage of This Year's Savings Relative to Last Year's:**
- Percentage = (This Year's Savings / Last Year's Savings) * 100
- Percentage = (0.129328S / 0.0825075S) * 100
- Percentage = (0.129328 / 0.0825075) * 100
- Percentage ≈ (1.567 / 1) * 100
- Percentage ≈ 156.7%

So, the amount saved this year was approximately 156.7% of the amount she saved last year.
이를 해결하려면 작년에 샌디가 절약한 금액과 올해 절약한 금액을 계산한 다음, 작년과 비교하여 올해 절약한 금액의 비율을 구해야 합니다.

작년의 샌디의 기본 급여를 S로 표시해 보겠습니다.

**작년:**
- 기본 급여: S
- 보너스: S의 3% = 0.03S
- 총 수입: S + 0.03S = 1.03S
- 급여에 대한 소득세: S의 15% = 0.15S
- 보너스에 대한 소득세: 0.03S의 20% = 0.006S
- 총 소득세: 0.15S + 0.006S = 0.156S
- 세후 소득: 1.03S - 0.156S = 0.874S
- 뮤추얼 펀드에 대한 투자: 1.03S의 5% = 0.0515S
- 투자 후 소득: 0.874S - 0.0515S = 0.8225S
- 뮤추얼 펀드 수익률: (상반기 4%, 하반기 6%로 0.0515S) = 0.0515S * (0.04 + 0.06) / 2 = 0.0515S * 0.05 = 0.002575S
- 뮤추얼 펀드 수익 후 소득: 0.8225S + 0.002575S = 0.825075S
- 저축: 0.825075S의 10% = 0.0825075S

**올해:**
- 기본급 인상: S의 10% = 0.1S
- 새 기본급: S + 0.1S = 1.1S
- 보너스: 1.1S의 7% = 0.077S
- 총 수입: 1.1S + 0.077S = 1.177S
- 급여에 대한 소득세: 1.1S의 17% = 0.187S
- 보너스에 대한 소득세: 0.077S의 22% = 0.01694S
- 총 소득세: 0.187S + 0.01694S = 0.20394S
- 세후 소득: 1.177S - 0.20394S = 0.97306S
- 뮤추얼 펀드에 대한 투자: 1.177S의 4% = 0.04708S, 1.177S의 6% = 0.07062S
- 총 투자: 0.04708S + 0.07062S = 0.1177S
- 투자 후 소득: 0.97306S - 0.1177S = 0.85536S
- 뮤추얼 펀드 수익률: 0.04708S * 0.07 + 0.07062S * 0.05 = 0.0032956S + 0.003531S = 0.0068266S
- 뮤추얼 펀드 수익 후 소득: 0.85536S + 0.0068266S = 0.8621866S
- 저축: 0.8621866S의 15% = 0.129328S

**작년과 비교한 올해 저축 비율:**
- 백분율 = (올해 저축액 / 작년 저축액) * 100
- 백분율 = (0.129328S / 0.0825075S) * 100
- 백분율 = (0.129328 / 0.0825075) * 100
- 백분율 ≈ (1.567 / 1) * 100
- 백분율 ≈ 156.7%

따라서 올해 절약한 금액은 작년에 절약한 금액의 약 156.7%입니다.