- Inception
- 1874, 1971
- bequest income
- 5000, 82000, 1117000
- donations
- 2501672, 9000, 471000, 23000, 19000, 2765000, 5000, 138000, 1118000, 83000
- employees
- 585, 553, 542, 525, 556, 677
- member count
- 500
- number of volunteers
- 1900, 1620, 1500, 1459, 1080
- short name
- IOP
- social media followers
- 189015, 207552, 230454, 45400
- total revenue
- 28883252, 76690000, 74595000, 67448000, 65833000, 72305000, 78795000, 74883000, 71921000, 82384000