<human>: Does the sentence "Besides increased efficiency of power plants, there was an increase in efficiency (between 1950 and 1973) of the railway utilization of this electricity with energy-intensity dropping from 218 to 124 kwh/10,000 gross tonne-km (of both passenger and freight trains) or a 43% drop." answer the question "What caused the energy efficiency to go up?"

OPTIONS:
- yes
- no
<bot>: yes