@Lalith I think you should look at the metrics of the text analytics API from Azure portal to plan your future usage based on the records that are already processed. The metric of interest is Processed Text Records. This metric can be seen from the Metrics tab of Azure portal of your resource. A processed text record metric is equivalent to 1000 characters. Please check the note under the data limits page for more details.
If an answer is helpful, please click on or upvote which might help other community members reading this thread.