Looking at the side effects of acetaminophen overdose etc. I think the percentage beside the adverse reaction is the percentage of adverse reactions with those symptoms. It is possible to get nervous system signs "Nervous system
Common (1% to 10%): Headache, dizziness
Frequency not reported: Dystonia"
https://www.drugs.com/sfx/paracetamol-side-effects.html"For Healthcare Professionals
Applies to acetaminophen: compounding powder, intravenous solution, oral capsule, oral granule effervescent, oral liquid, oral powder for reconstitution, oral suspension, oral tablet, oral tablet chewable, oral tablet disintegrating, oral tablet extended release, rectal suppository
General
In general, acetaminophen (the active ingredient contained in Paracetamol) is well-tolerated when administered in therapeutic doses. The most commonly reported adverse reactions have included nausea, vomiting, constipation. Injection site pain and injection site reaction have been reported with the IV product.[Ref]
Hepatic
Common (1% to 10%): Increased aspartate aminotransferase
Rare (less than 0.1%): Increased hepatic transaminases
Frequency not reported: Liver failure[Ref]
Gastrointestinal
Very common (10% or more): Nausea (up to 34%), Vomiting (up to 15%)
Common (1% to 10%): Abdominal pain, diarrhea, constipation, dyspepsia, enlarged abdomen
Frequency not reported: Dry mouth[Ref]
Hypersensitivity
Postmarketing reports: Anaphylaxis, hypersensitivity reactions[Ref]
Hematologic
Common (1% to 10%): Anemia, postoperative hemorrhage
Very rare (less than 0.01%): Thrombocytopenia, leucopenia, neutropenia[Ref]
Dermatologic
Common (1% to 10%): Rash, pruritus
Rare (less than 0.1%): Serious skin reactions such as acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, and toxic epidermal necrolysis
Very rare (less than 0.01%): Pemphigoid reaction, pustular rash, Lyell syndrome
:[Ref]
Respiratory
Common (1% to 10%): Dyspnea, abnormal breath sounds, pulmonary edema, hypoxia, pleural effusion, stridor, wheezing, coughing[Ref]
Cardiovascular
Common (1% to 10%): Peripheral edema, hypertension, hypotension, tachycardia, chest pain[Ref]
Metabolic
Common (1% to 10%): Hypokalemia, hyperglycemia[Ref]
Nervous system
Common (1% to 10%): Headache, dizziness
Frequency not reported: Dystonia
Musculoskeletal
Common (1% to 10%): Muscle spasms, trismus
Psychiatric
Common (1% to 10%): Insomnia, anxiety
Genitourinary
Common (1% to 10%): Oliguria
Local
Common (1% to 10%): Infusion site pain, injection site reactions
Ocular
Common (1% to 10%): Periorbital edema
Other
Common (1% to 10%): Pyrexia, fatigue
Rare (0.01% to 0.1%): Malaise
