Chinese agriculture is 55.6% more efficient than American agriculture, in terms of people fed per he
"China feeds more people than India per cropland hectare with 8.4 people fed with delivered calories...US croplands feed 5.4 people ha−1 but could feed 16.1 people ha−1 if the current 34% efficiency rose to 100%"
Calculation: 8.4/5.4=1.556, so 8.4 is 55.6% greater than 5.4.
Emily S Cassidy et al., “Redefining agricultural yields: from tonnes to people nourished per hectare,” Environmental Research Letters, 8, no. 3, (2013), accessed December 12, 2014, http://iopscience.iop.org/1748-9326/8/3/034015/article