Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the mean year of marriage when her age was more than 19 and his age was 30?

### Inputs:
table_name: table, columns: ['Year of Marriage', 'Name', 'Her Age', 'His Age', '# of Children']

### Response:
SELECT AVG Year of Marriage FROM table WHERE Her Age > 19 AND His Age = 30