An investor bought a 3-year zero-coupon bond in Year 0, when the 1-year zero rate was 4.1% pa, the 2-year zero rate was 5.2% pa and the 3-year zero rate was 5.7% pa. The investor sold the bond two years later. Zero-rate curves for various dates are shown in the table below.

Term (years)	Year 0	Year 1	Year 2	Year 3
1	4.1%	7.2%	10.0%	10.4%
2	5.2%	8.2%	10.1%	10.4%
3	5.7%	8.8%	10.2%	10.4%

What is the investor's holding period rate of return (pa)?