MacBook Pro battery dies when sleeping after charging to a full battery.

I have only used my MacBook Pro sparsely in the past two weeks. Both times, the computer was dead so I fully charged it to 100%. After maybe ten minutes of usage, I put it down. A few days later, when I open my computer, the MacBook was completely out of battery. This is despite having no applications running (supposedly) and in sleep mode with the lid down. What is causing my battery to die while sleeping? I checked the battery health and it reported: "normal". It is rather annoying having to boot up my MacBook with a charger every time I want to use it. What can I do to fix this issue?