ASUS ZenFone 2 Laser ZE550KL Wasteful ?

Hi, Everyone. I'm a new member here :)

I had problem with my phone.
Not long ago, I bought a new phone "ASUS ZenFone 2 Laser 16 GB ZE550KL" (Lollipop 5.0)
I felt my phone battery is so wasteful.
This is my chronology :
After I bought this phone, I immediately charge my phone until full battery.
After I charge my phone, during one full day after I charge my phone. I don't use my phone at all.
But, my phone battery is reduced 5%.
Everyday my phone always reduced at least 5% battery, Although I don't use.
I'm so frustrated about it :crying:
Has anyone experienced like me ? or there is a problem of my phone ?
Master, give me advice and tips. About it and How to keep my phone is so efficient battery ?

Thankyou very much master-master here :)

*My Phone Spesification :
5.5"
4G LTE
Android Lollipop 5.0
Internal 16GB
Ram 2GB
Chipset Qualcomm MSM8916 Snapdragon 410
Qualcomm MSM8939 Snapdragon 615
CPU Quad-core 1.2 GHz Cortex-A53
Quad-core 1.5 GHz Cortex-A53 & quad-core 1.0 GHz Cortex-A53
GPU Adreno 306
Adreno 405
Removable Li-Po 3000 mAh battery