Hi Belinda,
Unfortunately CPI is not a good indicator of salary movements. In the last few years increases have outstripped CPI significantly, and now CPI may in fact be higher than average movements! Referencing CPI can be a good idea though in arguing your case for a specific budget (ie. if you give only 2% when CPI is 2.5% then in effect people's real salaries are going backwards). I believe it is at 2.5% at the moment.
You should look to some reliable benchmark data to actually compare where each of your employees sits relative to the market and then consider what the organisation can afford in this market. I'm a little biased as I work for a remuneration company which produces a great general industry salary survey (which covers
HR & Finance) which I would recommend. I'm pretty sure I'm not meant to advertise on here though, so if you are interested then please private message me and I can provide some more details.