I've 7000 leads in my Zoho CRM. Some leads may have notes and others may not.

I'm using below api to retrieve notes:
https://crm.zoho.eu/crm/private/json/Notes/getRelatedRecords?authtoken=mytoken&scope=crmapi&fromIndex=1&toIndex=200&version=4&parentModule=Leads&id=27304000000221637

For every leads, I've to call above api to retrieve notes. My api calls count per day is 5000 which is not enough for me to call all my 7000 leads. The limit gets exceeded once I setup app for first time and couldn't use for rest of day.

Is there any other api, to get list of notes not based on leads/contacts to accommodate api calls per day within limit.

Thanks,
Guna