Arranging data for time series Arima modelling

[ppp]

Hello,

I am trying to do time series ARIMA modelling for my data. The data has variable year 1997-2012 and is subgrouped by 8 age group .It also consists of percentage of members for each year for each age group.

I am trying to use this data to analyze which ARIMA model would be suitable and forecast for next 5 years for each age-group. I am struggling as to how to arrange my data so this can be carried out.

It would be helpful if anyone could help me by giving ideas.