Juries are Acquittal Minded
The standard of proof in criminal trials is beyond all reasonable doubt and so very high meaning that if the jury has any doubt then they should find the d not guilty. Perhaps due to lack of legal expertise and the worry of convicting an innocent person, d's are more likely to be acquitted.
Typically, juries acquit 60% of d's compared with only 20% acquitted in the Magistrates court. In the interests of justice it is better to be cautious and find the d not guilty than take an innocent person's freedom, but the downside could be that a guilty person is acquitted and released back into society simply because of a very convincing defence barrister.
In contrast, the vast majority of acquittals in the Crown Court are the result of the judge stopping the trial due to insufficient evidence being presented by the prosecution so the statistic is misleading.