The open interest can be found at the web site of the exchange where the contract is listed.
The exchange willnot break down the open interest by participant. For that you will have to go to the committment of traders (COT) report which is released every friday. I believe it published by the CFTC. It breaks down the open interest by paticipant (commercial vs non commercial). It can be extremely useful because it can give a hint on what participants may may do to a nearby spread. For example, if funds are long the nearby and there is little/ no chance of standing for delivery, the funds will be forced to roll their position ( usually into the following month but not always) and push the spread towards full carry.
With respect to crude spreads narrowing, I think that can be attributed to deliverable stocks in cushing being removed. This reduces the threat of delivery and compels the short to roll at a lesser carrying charge. The ability of commercials to remove or add to deliverable stocks gives them the ability to greatly influence a spread and therefore the direction of the flat price. I believe that this is how some of the nearby crude spreads traded as wide as $8 over the past 18 months. However the nearby spreads cannot continue to trade at those kinds of levels because it becomes too costly for the long. For example if a long was established at $75 and the position was rolled fro 1 year at $2/month the breakeven price at the end of the year would be $95, not really a very good proposition. Thus, spreads moving sigfnificantly beyond full carry threatens the viability of a contract.
The wheat contract has struggled with this for some time.
The above identifies two factors that will influence a spread, composition of the open interest and threat of delivery. There is more to it than that but it is a start. Hope it helps.
Regards, local.