A 2015 article published by the American Journal of Preventive Medicine studied the effects of an increase in alcohol prices on the incidence of new cases of sexually transmitted diseases. In particular, the researchers studied the effects that a Maryland policy increasing alcohol taxes had on the decline in gonorrhea cases. The report concluded that an increase in the alcohol tax rate by 3% resulted in 1,600 fewer cases of gonorrhea. Assume that prior to the tax increase, the number of gonorrhea cases was 7,450. Use the midpoint method to determine the percent decrease in gonorrhea cases, and then calculate the cross-price elasticity of demand between alcohol and the incidence of gonorrhea. According to your estimate of this cross-price elasticity of demand, are alcohol and gonorrhea complements or substitutes?