user: Question: What's the total percent of the $40-50K ones that have N/A?
Columns: ['Data', 'Headcount', 'Percent of total', 'Less than $25,000', '$25,000 to $40,000', '$40,000 to $50,000', '$50,000 to $60,000', '$60,000 to $70,000', '$70,000 to $80,000', 'More than $80,000', 'Mean']
Types: ['text', 'real', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Educational administrators', 1965.0, '2.2%', '1.93%', '0.51%', '0.92%', '0.97%', '1.42%', '2.85%', '90.08%', '$116,855']
SQL:

assistant: SELECT SUM("Percent of total") FROM "Table" WHERE "$40,000 to $50,000" = 'N/A';