cov = number of bases / length of genome
	relative abundance = [(cov) / sum(cov for all genomes)] * 100

def relative_abundance(coverage):
	"""
	cov = number of bases / length of genome
	relative abundance = [(cov) / sum(cov for all genomes)] * 100
	"""
	relative = {}
	sums = []
	for genome in coverage:
		for cov in coverage[genome]:
			sums.append(0)
		break
	for genome in coverage:
		index = 0
		for cov in coverage[genome]:
			sums[index] += cov
			index += 1
	for genome in coverage:
		index = 0
		relative[genome] = []
		for cov in coverage[genome]:
			if sums[index] == 0:
				relative[genome].append(0)
			else:
				relative[genome].append((cov / sums[index]) * float(100))
			index += 1
	return relative