You're assuming that NI is purely for healthcare when it also covers other benefits that cost a signficant amount to the public purse, e.g. the state pension, so your figures don't stack up I'm afraid.
You're assuming that NI is purely for healthcare when it also covers other benefits that cost a signficant amount to the public purse, e.g. the state pension, so your figures don't stack up I'm afraid.