Back in January the Electoral Commission recommended that the question on the independence referendum ballot paper should read:

'Should Scotland be an independent country?' Ever since politicians and campaigners have been doing their best to persuade us the answer to that question should either be 'Yes' or 'No'.

Their efforts have produced little tangible reward. For, as our poll of polls (below) shows, the balance of public opinion is much the same now as it has been throughout the year.

Once the Don't Knows and Won't Says are removed (after all, there will be no chance to give such a response on polling day), on average the Yes vote has stood at 39% in eight polls conducted since the beginning of October. Conversely this same calculation puts the No vote on 61%.

These two figures are exactly the same as the average for 10 polls conducted between July and September - most of which interviewed people in the four weeks immediately prior to the September 18 'a year to go' anniversary.

Meanwhile, the equivalent calculation also produces an almost identical result for the period between February and May, during which nine published polls were conducted. In these Yes stood at 38%, No on 62%.

The No side have spent much of this year emphasising the alleged uncertainties of independence, not least in a regular series of UK government White Papers on the implications and consequences of independence.

Dubbed 'Project Fear' by the nationalist camp, the effort has evidently cut little ice with the public.

Equally, however, the Yes side say their activists have been out on the streets and knocking on doors, and that when they explain the case for independence to people their commitment to the No cause is undermined.

All that can be said, is this has yet to register itself in the published opinion polls.

Mind you, the apparent stability of public opinion is only evident in a poll of polls. Individually, the polling companies are poles apart - as they have been all year.

At one end of the spectrum lies Panelbase. Its two most recent polls, in October and November, both put the Yes vote on 45% (once the Don't Knows are excluded).

Every single Panelbase poll conducted this year (bar one) has put that figure at 44% or 45%, making it consistently the most optimistic pollster so far as the Yes side are concerned.

At the other end sits Progressive Scottish Opinion, who most recently put the Yes vote at 33% after estimating it to be as low as 31% in September.

Other pollsters, such as TNS BMRB, Ipsos MORI and YouGov sit somewhere in between these two extremes. They all currently reckon that the Yes vote stands between 37% and 39% - much as they did at the beginning of this year.

So while there appears to be little doubt that public opinion has remained largely unmoved by the year's blandishments and threats, there continues to be considerable uncertainty about exactly how far Yes are behind. If Panelbase is correct, the winning post is at least in the Yes camp's sights. If, on the other hand, Progressive is correct, the task of securing a majority Yes vote looks Herculean.

But what about the most recent White Paper of all, that is the independence prospectus unveiled at the end of the last month by the Scottish Government? We were told this would address uncertainties about what independence would bring and thus be a 'game changer' in the battle for hearts and minds. Has this not begun to move the pendulum in the nationalists' direction?

Three polls have been conducted since the White Paper was published - by Progressive, Ipsos MORI and YouGov. As we have already seen. Progressive's poll registered a 2% swing to the Yes side since September (once the Don't Knows were excluded). Ipsos MORI also detected a pro-Yes swing - which it put at 3% - while YouGov found one of 1% (in both cases since September).

So the White Paper may have had some impact - but one that looks like a ripple on the sea of public opinion rather than a 'game changer'.

If the Yes side is to make more significant progress, it will need above all to persuade Scots of the economic benefits of independence. Of all the questions people have about what independence might bring, none seems to matter more than whether they think it would herald a stronger or a weaker Scottish economy.

So far the pro-independence campaign has failed to achieve any success in its attempts to advance its economic case.

This can be seen in our second chart, which shows how people have responded when on various occasions during the past three years YouGov have asked them whether Scotland would be economically or financially better or worse off under independence.

As long ago as May 2011, shortly after the SNP's stunning success in that month's Scottish Parliament election, as many as 47% felt the country would be worse off, while only 28% reckoned it would be better off. The latest figures are almost exactly the same; all the Yes side might have achieved is to reverse an even more pessimistic mood evident in October last year.

However, even whether that much has been achieved is in doubt. Back in February of last year Panelbase reported the proportion of people who reckoned an independent Scotland would be better off, 36%, almost matched the percentage who felt it would be worse off, 39%.

But in their most recent poll pessimists (44%) clearly outnumbered optimists (32%).

There may still be nine months to go to polling day but a key lesson of the past nine seems to be that many people have already made up their minds. If opinion is eventually to shift, one side or the other will probably need to start campaigning brilliantly - or badly.