Hi,
Refer the code
from odoo import models, fields, api

class YourModel(models.Model):
    _name = 'your.model'
    _description = 'Your Model'

    field1 = fields.Float(string='Field 1')
    field2 = fields.Float(string='Field 2')
    percentage = fields.Float(string='Percentage', compute='_compute_percentage', store=True)

    @api.depends('field1', 'field2')
    def _compute_percentage(self):
        for record in self:
            if record.field2 != 0:
                record.percentage = (record.field1 / record.field2) * 100
            else:
                record.percentage = 0.0

<record id="view_your_model_pivot" model="ir.ui.view">
<field name="name">your.model.pivot</field>
<field name="model">your.model</field>
    <field name="arch" type="xml">
        <pivot>
            <field name="field1" type="measure" string="Field 1"/>
            <field name="field2" type="measure" string="Field 2"/>
            <field name="percentage" type="measure" string="Percentage"/>
        </pivot>
    </field>
</record>

Hope it helps