Voltage and potential difference are the same thing. Nobody out of school uses the latter term. Voltage is the potential in an electrical circuit to cause the flow of current (ie, electrons). wikipedia: Voltage is commonly used as a short name for electrical potential difference.
Population of Jamaica 2014. As of 1 January 2015, the population of Jamaica was estimated to be 2 767 704 people. This is an increase of 0.73 % (20 112 people) compared to population of 2 747 592 the year before. In 2014 the natural increase was positive, as the number of births exceeded the number of deaths by 34 785. Due to external migration, the population declined by 14 672. The sex ratio of the total population was 0.969 (969 males per 1 000 females) which is lower than global sex ratio.
Jamaica has a total population of 2.7 million people. Retirement with an immediate pension can be as early as age 50 years and as late as age 70 years. The average age at death for persons receiving a pension from a pension plan is in the late seventies to early eighties; so retirees need an income for many years after ceasing employment.