The correct sequence of parts that carry cardiac impulses is

SA node > AV node > AV bundle (bundle of HIS) > Bundle branches > Purkinje fibers.

The sinoatrial (SA) node, located in the right atrium,  produces an electric impulse by contraction. This impulse travels to the atrioventricular (AV) node, located at the partition of the atria. There is a tenth of a second delay in the impulse as the AV node contracts and sends the impulse through the bundle's branches to the ventricles. The bundle branches further divide into Purkinje fibers in the ventricle walls. When the impulse reaches the Purkinje fibers, they make the ventricles walls to contract.

not sure if this what   you'r looking for would be percent composition

a = executive branch; b = judicial branch