Hello, In common size analysis of cash flow. I have calculated as % of sale for that year. can you tell me its interpretation.

Cash Flow	2018	2019	2020	2021
Net cash flows from operating activities	15%	14%	15%	15%
Net cash flows from investing activities	7%	-10%	-17%	-4%
Net cash flows from financing activities	-21%	-13%	5%	-14%
Net cash flow	0.3%	-8%	4%	-3%